phpmyadmin working

1 files changed, 1963 insertions, 0 deletions

diff --git a/srcs/phpmyadmin/libraries/classes/Database/Qbe.php b/srcs/phpmyadmin/libraries/classes/Database/Qbe.php
new file mode 100644
index 0000000..27116d0
--- /dev/null
+++ b/srcs/phpmyadmin/libraries/classes/Database/Qbe.php
@@ -0,0 +1,1963 @@
+<?php
+/* vim: set expandtab sw=4 ts=4 sts=4: */
+/**
+ * Handles DB QBE search
+ *
+ * @package PhpMyAdmin
+ */
+declare(strict_types=1);
+
+namespace PhpMyAdmin\Database;
+
+use PhpMyAdmin\Core;
+use PhpMyAdmin\DatabaseInterface;
+use PhpMyAdmin\Message;
+use PhpMyAdmin\Relation;
+use PhpMyAdmin\SavedSearches;
+use PhpMyAdmin\Table;
+use PhpMyAdmin\Template;
+use PhpMyAdmin\Url;
+use PhpMyAdmin\Util;
+
+/**
+ * Class to handle database QBE search
+ *
+ * @package PhpMyAdmin
+ */
+class Qbe
+{
+    /**
+     * Database name
+     *
+     * @access private
+     * @var string
+     */
+    private $_db;
+    /**
+     * Table Names (selected/non-selected)
+     *
+     * @access private
+     * @var array
+     */
+    private $_criteriaTables;
+    /**
+     * Column Names
+     *
+     * @access private
+     * @var array
+     */
+    private $_columnNames;
+    /**
+     * Number of columns
+     *
+     * @access private
+     * @var integer
+     */
+    private $_criteria_column_count;
+    /**
+     * Number of Rows
+     *
+     * @access private
+     * @var integer
+     */
+    private $_criteria_row_count;
+    /**
+     * Whether to insert a new column
+     *
+     * @access private
+     * @var array
+     */
+    private $_criteriaColumnInsert;
+    /**
+     * Whether to delete a column
+     *
+     * @access private
+     * @var array
+     */
+    private $_criteriaColumnDelete;
+    /**
+     * Whether to insert a new row
+     *
+     * @access private
+     * @var array
+     */
+    private $_criteriaRowInsert;
+    /**
+     * Whether to delete a row
+     *
+     * @access private
+     * @var array
+     */
+    private $_criteriaRowDelete;
+    /**
+     * Already set criteria values
+     *
+     * @access private
+     * @var array
+     */
+    private $_criteria;
+    /**
+     * Previously set criteria values
+     *
+     * @access private
+     * @var array
+     */
+    private $_prev_criteria;
+    /**
+     * AND/OR relation b/w criteria columns
+     *
+     * @access private
+     * @var array
+     */
+    private $_criteriaAndOrColumn;
+    /**
+     * AND/OR relation b/w criteria rows
+     *
+     * @access private
+     * @var array
+     */
+    private $_criteriaAndOrRow;
+    /**
+     * Large width of a column
+     *
+     * @access private
+     * @var string
+     */
+    private $_realwidth;
+    /**
+     * Minimum width of a column
+     *
+     * @access private
+     * @var int
+     */
+    private $_form_column_width;
+    /**
+     * Selected columns in the form
+     *
+     * @access private
+     * @var array
+     */
+    private $_formColumns;
+    /**
+     * Entered aliases in the form
+     *
+     * @access private
+     * @var array
+     */
+    private $_formAliases;
+    /**
+     * Chosen sort options in the form
+     *
+     * @access private
+     * @var array
+     */
+    private $_formSorts;
+    /**
+     * Chosen sort orders in the form
+     *
+     * @access private
+     * @var array
+     */
+    private $_formSortOrders;
+    /**
+     * Show checkboxes in the form
+     *
+     * @access private
+     * @var array
+     */
+    private $_formShows;
+    /**
+     * Entered criteria values in the form
+     *
+     * @access private
+     * @var array
+     */
+    private $_formCriterions;
+    /**
+     * AND/OR column radio buttons in the form
+     *
+     * @access private
+     * @var array
+     */
+    private $_formAndOrCols;
+    /**
+     * AND/OR row radio buttons in the form
+     *
+     * @access private
+     * @var array
+     */
+    private $_formAndOrRows;
+    /**
+     * New column count in case of add/delete
+     *
+     * @access private
+     * @var integer
+     */
+    private $_new_column_count;
+    /**
+     * New row count in case of add/delete
+     *
+     * @access private
+     * @var integer
+     */
+    private $_new_row_count;
+    /**
+     * List of saved searches
+     *
+     * @access private
+     * @var array
+     */
+    private $_savedSearchList = null;
+    /**
+     * Current search
+     *
+     * @access private
+     * @var SavedSearches
+     */
+    private $_currentSearch = null;
+
+    /**
+     * @var Relation
+     */
+    private $relation;
+
+    /**
+     * @var DatabaseInterface
+     */
+    public $dbi;
+
+    /**
+     * @var Template
+     */
+    public $template;
+
+    /**
+     * Public Constructor
+     *
+     * @param Relation          $relation        Relation object
+     * @param Template          $template        Template object
+     * @param DatabaseInterface $dbi             DatabaseInterface object
+     * @param string            $dbname          Database name
+     * @param array             $savedSearchList List of saved searches
+     * @param SavedSearches     $currentSearch   Current search id
+     */
+    public function __construct(
+        Relation $relation,
+        Template $template,
+        $dbi,
+        $dbname,
+        array $savedSearchList = [],
+        $currentSearch = null
+    ) {
+        $this->_db = $dbname;
+        $this->_savedSearchList = $savedSearchList;
+        $this->_currentSearch = $currentSearch;
+        $this->dbi = $dbi;
+        $this->relation = $relation;
+        $this->template = $template;
+
+        $this->_loadCriterias();
+        // Sets criteria parameters
+        $this->_setSearchParams();
+        $this->_setCriteriaTablesAndColumns();
+    }
+
+    /**
+     * Initialize criterias
+     *
+     * @return static
+     */
+    private function _loadCriterias()
+    {
+        if (null === $this->_currentSearch
+            || null === $this->_currentSearch->getCriterias()
+        ) {
+            return $this;
+        }
+
+        $criterias = $this->_currentSearch->getCriterias();
+        $_POST = $criterias + $_POST;
+
+        return $this;
+    }
+
+    /**
+     * Getter for current search
+     *
+     * @return SavedSearches
+     */
+    private function _getCurrentSearch()
+    {
+        return $this->_currentSearch;
+    }
+
+    /**
+     * Sets search parameters
+     *
+     * @return void
+     */
+    private function _setSearchParams()
+    {
+        $criteriaColumnCount = $this->_initializeCriteriasCount();
+
+        $this->_criteriaColumnInsert = Core::ifSetOr(
+            $_POST['criteriaColumnInsert'],
+            null,
+            'array'
+        );
+        $this->_criteriaColumnDelete = Core::ifSetOr(
+            $_POST['criteriaColumnDelete'],
+            null,
+            'array'
+        );
+
+        $this->_prev_criteria = isset($_POST['prev_criteria'])
+            ? $_POST['prev_criteria']
+            : [];
+        $this->_criteria = isset($_POST['criteria'])
+            ? $_POST['criteria']
+            : array_fill(0, $criteriaColumnCount, '');
+
+        $this->_criteriaRowInsert = isset($_POST['criteriaRowInsert'])
+            ? $_POST['criteriaRowInsert']
+            : array_fill(0, $criteriaColumnCount, '');
+        $this->_criteriaRowDelete = isset($_POST['criteriaRowDelete'])
+            ? $_POST['criteriaRowDelete']
+            : array_fill(0, $criteriaColumnCount, '');
+        $this->_criteriaAndOrRow = isset($_POST['criteriaAndOrRow'])
+            ? $_POST['criteriaAndOrRow']
+            : array_fill(0, $criteriaColumnCount, '');
+        $this->_criteriaAndOrColumn = isset($_POST['criteriaAndOrColumn'])
+            ? $_POST['criteriaAndOrColumn']
+            : array_fill(0, $criteriaColumnCount, '');
+        // sets minimum width
+        $this->_form_column_width = 12;
+        $this->_formColumns = [];
+        $this->_formSorts = [];
+        $this->_formShows = [];
+        $this->_formCriterions = [];
+        $this->_formAndOrRows = [];
+        $this->_formAndOrCols = [];
+    }
+
+    /**
+     * Sets criteria tables and columns
+     *
+     * @return void
+     */
+    private function _setCriteriaTablesAndColumns()
+    {
+        // The tables list sent by a previously submitted form
+        if (Core::isValid($_POST['TableList'], 'array')) {
+            foreach ($_POST['TableList'] as $each_table) {
+                $this->_criteriaTables[$each_table] = ' selected="selected"';
+            }
+        } // end if
+        $all_tables = $this->dbi->query(
+            'SHOW TABLES FROM ' . Util::backquote($this->_db) . ';',
+            DatabaseInterface::CONNECT_USER,
+            DatabaseInterface::QUERY_STORE
+        );
+        $all_tables_count = $this->dbi->numRows($all_tables);
+        if (0 == $all_tables_count) {
+            Message::error(__('No tables found in database.'))->display();
+            exit;
+        }
+        // The tables list gets from MySQL
+        while (list($table) = $this->dbi->fetchRow($all_tables)) {
+            $columns = $this->dbi->getColumns($this->_db, $table);
+
+            if (empty($this->_criteriaTables[$table])
+                && ! empty($_POST['TableList'])
+            ) {
+                $this->_criteriaTables[$table] = '';
+            } else {
+                $this->_criteriaTables[$table] = ' selected="selected"';
+            } //  end if
+
+            // The fields list per selected tables
+            if ($this->_criteriaTables[$table] == ' selected="selected"') {
+                $each_table = Util::backquote($table);
+                $this->_columnNames[]  = $each_table . '.*';
+                foreach ($columns as $each_column) {
+                    $each_column = $each_table . '.'
+                        . Util::backquote($each_column['Field']);
+                    $this->_columnNames[] = $each_column;
+                    // increase the width if necessary
+                    $this->_form_column_width = max(
+                        mb_strlen($each_column),
+                        $this->_form_column_width
+                    );
+                } // end foreach
+            } // end if
+        } // end while
+        $this->dbi->freeResult($all_tables);
+
+        // sets the largest width found
+        $this->_realwidth = $this->_form_column_width . 'ex';
+    }
+    /**
+     * Provides select options list containing column names
+     *
+     * @param integer $column_number Column Number (0,1,2) or more
+     * @param string  $selected      Selected criteria column name
+     *
+     * @return string HTML for select options
+     */
+    private function _showColumnSelectCell($column_number, $selected = '')
+    {
+        return $this->template->render('database/qbe/column_select_cell', [
+            'column_number' => $column_number,
+            'column_names' => $this->_columnNames,
+            'selected' => $selected,
+        ]);
+    }
+
+    /**
+     * Provides select options list containing sort options (ASC/DESC)
+     *
+     * @param integer $columnNumber Column Number (0,1,2) or more
+     * @param string  $selected     Selected criteria 'ASC' or 'DESC'
+     *
+     * @return string HTML for select options
+     */
+    private function _getSortSelectCell(
+        $columnNumber,
+        $selected = ''
+    ) {
+        return $this->template->render('database/qbe/sort_select_cell', [
+            'real_width' => $this->_realwidth,
+            'column_number' => $columnNumber,
+            'selected' => $selected,
+        ]);
+    }
+
+    /**
+     * Provides select options list containing sort order
+     *
+     * @param integer $columnNumber Column Number (0,1,2) or more
+     * @param integer $sortOrder    Sort order
+     *
+     * @return string HTML for select options
+     */
+    private function _getSortOrderSelectCell($columnNumber, $sortOrder)
+    {
+        $totalColumnCount = $this->_getNewColumnCount();
+        return $this->template->render('database/qbe/sort_order_select_cell', [
+            'total_column_count' => $totalColumnCount,
+            'column_number' => $columnNumber,
+            'sort_order' => $sortOrder,
+        ]);
+    }
+
+    /**
+     * Returns the new column count after adding and removing columns as instructed
+     *
+     * @return int new column count
+     */
+    private function _getNewColumnCount()
+    {
+        $totalColumnCount = $this->_criteria_column_count;
+        if (! empty($this->_criteriaColumnInsert)) {
+            $totalColumnCount += count($this->_criteriaColumnInsert);
+        }
+        if (! empty($this->_criteriaColumnDelete)) {
+            $totalColumnCount -= count($this->_criteriaColumnDelete);
+        }
+        return $totalColumnCount;
+    }
+
+    /**
+     * Provides search form's row containing column select options
+     *
+     * @return string HTML for search table's row
+     */
+    private function _getColumnNamesRow()
+    {
+        $html_output = '<tr class="noclick">';
+        $html_output .= '<th>' . __('Column:') . '</th>';
+        $new_column_count = 0;
+        for ($column_index = 0; $column_index < $this->_criteria_column_count; $column_index++) {
+            if (isset($this->_criteriaColumnInsert[$column_index])
+                && $this->_criteriaColumnInsert[$column_index] == 'on'
+            ) {
+                $html_output .= $this->_showColumnSelectCell(
+                    $new_column_count
+                );
+                $new_column_count++;
+            }
+            if (! empty($this->_criteriaColumnDelete)
+                && isset($this->_criteriaColumnDelete[$column_index])
+                && $this->_criteriaColumnDelete[$column_index] == 'on'
+            ) {
+                continue;
+            }
+            $selected = '';
+            if (isset($_POST['criteriaColumn'][$column_index])) {
+                $selected = $_POST['criteriaColumn'][$column_index];
+                $this->_formColumns[$new_column_count]
+                    = $_POST['criteriaColumn'][$column_index];
+            }
+            $html_output .= $this->_showColumnSelectCell(
+                $new_column_count,
+                $selected
+            );
+            $new_column_count++;
+        } // end for
+        $this->_new_column_count = $new_column_count;
+        $html_output .= '</tr>';
+        return $html_output;
+    }
+
+    /**
+     * Provides search form's row containing column aliases
+     *
+     * @return string HTML for search table's row
+     */
+    private function _getColumnAliasRow()
+    {
+        $html_output = '<tr class="noclick">';
+        $html_output .= '<th>' . __('Alias:') . '</th>';
+        $new_column_count = 0;
+
+        for ($colInd = 0; $colInd < $this->_criteria_column_count; $colInd++) {
+            if (! empty($this->_criteriaColumnInsert)
+                && isset($this->_criteriaColumnInsert[$colInd])
+                && $this->_criteriaColumnInsert[$colInd] == 'on'
+            ) {
+                $html_output .= '<td class="center">';
+                $html_output .= '<input type="text"'
+                    . ' name="criteriaAlias[' . $new_column_count . ']">';
+                $html_output .= '</td>';
+                $new_column_count++;
+            } // end if
+
+            if (! empty($this->_criteriaColumnDelete)
+                && isset($this->_criteriaColumnDelete[$colInd])
+                && $this->_criteriaColumnDelete[$colInd] == 'on'
+            ) {
+                continue;
+            }
+
+            $tmp_alias = '';
+            if (! empty($_POST['criteriaAlias'][$colInd])) {
+                $tmp_alias
+                    = $this->_formAliases[$new_column_count]
+                        = $_POST['criteriaAlias'][$colInd];
+            }// end if
+
+            $html_output .= '<td class="center">';
+            $html_output .= '<input type="text"'
+                . ' name="criteriaAlias[' . $new_column_count . ']"'
+                . ' value="' . htmlspecialchars($tmp_alias) . '">';
+            $html_output .= '</td>';
+            $new_column_count++;
+        } // end for
+        $html_output .= '</tr>';
+        return $html_output;
+    }
+
+    /**
+     * Provides search form's row containing sort(ASC/DESC) select options
+     *
+     * @return string HTML for search table's row
+     */
+    private function _getSortRow()
+    {
+        $html_output = '<tr class="noclick">';
+        $html_output .= '<th>' . __('Sort:') . '</th>';
+        $new_column_count = 0;
+
+        for ($colInd = 0; $colInd < $this->_criteria_column_count; $colInd++) {
+            if (! empty($this->_criteriaColumnInsert)
+                && isset($this->_criteriaColumnInsert[$colInd])
+                && $this->_criteriaColumnInsert[$colInd] == 'on'
+            ) {
+                $html_output .= $this->_getSortSelectCell($new_column_count);
+                $new_column_count++;
+            } // end if
+
+            if (! empty($this->_criteriaColumnDelete)
+                && isset($this->_criteriaColumnDelete[$colInd])
+                && $this->_criteriaColumnDelete[$colInd] == 'on'
+            ) {
+                continue;
+            }
+            // If they have chosen all fields using the * selector,
+            // then sorting is not available, Fix for Bug #570698
+            if (isset($_POST['criteriaSort'][$colInd])
+                && isset($_POST['criteriaColumn'][$colInd])
+                && mb_substr($_POST['criteriaColumn'][$colInd], -2) == '.*'
+            ) {
+                $_POST['criteriaSort'][$colInd] = '';
+            } //end if
+
+            $selected = '';
+            if (isset($_POST['criteriaSort'][$colInd])) {
+                $this->_formSorts[$new_column_count]
+                    = $_POST['criteriaSort'][$colInd];
+
+                if ($_POST['criteriaSort'][$colInd] == 'ASC') {
+                    $selected = 'ASC';
+                } elseif ($_POST['criteriaSort'][$colInd] == 'DESC') {
+                    $selected = 'DESC';
+                }
+            } else {
+                $this->_formSorts[$new_column_count] = '';
+            }
+
+            $html_output .= $this->_getSortSelectCell(
+                $new_column_count,
+                $selected
+            );
+            $new_column_count++;
+        } // end for
+        $html_output .= '</tr>';
+        return $html_output;
+    }
+
+    /**
+     * Provides search form's row containing sort order
+     *
+     * @return string HTML for search table's row
+     */
+    private function _getSortOrder()
+    {
+        $html_output = '<tr class="noclick">';
+        $html_output .= '<th>' . __('Sort order:') . '</th>';
+        $new_column_count = 0;
+
+        for ($colInd = 0; $colInd < $this->_criteria_column_count; $colInd++) {
+            if (! empty($this->_criteriaColumnInsert)
+                && isset($this->_criteriaColumnInsert[$colInd])
+                && $this->_criteriaColumnInsert[$colInd] == 'on'
+            ) {
+                $html_output .= $this->_getSortOrderSelectCell(
+                    $new_column_count,
+                    null
+                );
+                $new_column_count++;
+            } // end if
+
+            if (! empty($this->_criteriaColumnDelete)
+                && isset($this->_criteriaColumnDelete[$colInd])
+                && $this->_criteriaColumnDelete[$colInd] == 'on'
+            ) {
+                continue;
+            }
+
+            $sortOrder = null;
+            if (! empty($_POST['criteriaSortOrder'][$colInd])) {
+                $sortOrder
+                    = $this->_formSortOrders[$new_column_count]
+                        = $_POST['criteriaSortOrder'][$colInd];
+            }
+
+            $html_output .= $this->_getSortOrderSelectCell(
+                $new_column_count,
+                $sortOrder
+            );
+            $new_column_count++;
+        } // end for
+        $html_output .= '</tr>';
+        return $html_output;
+    }
+
+    /**
+     * Provides search form's row containing SHOW checkboxes
+     *
+     * @return string HTML for search table's row
+     */
+    private function _getShowRow()
+    {
+        $html_output = '<tr class="noclick">';
+        $html_output .= '<th>' . __('Show:') . '</th>';
+        $new_column_count = 0;
+        for ($column_index = 0; $column_index < $this->_criteria_column_count; $column_index++) {
+            if (! empty($this->_criteriaColumnInsert)
+                && isset($this->_criteriaColumnInsert[$column_index])
+                && $this->_criteriaColumnInsert[$column_index] == 'on'
+            ) {
+                $html_output .= '<td class="center">';
+                $html_output .= '<input type="checkbox"'
+                    . ' name="criteriaShow[' . $new_column_count . ']">';
+                $html_output .= '</td>';
+                $new_column_count++;
+            } // end if
+            if (! empty($this->_criteriaColumnDelete)
+                && isset($this->_criteriaColumnDelete[$column_index])
+                && $this->_criteriaColumnDelete[$column_index] == 'on'
+            ) {
+                continue;
+            }
+            if (isset($_POST['criteriaShow'][$column_index])) {
+                $checked_options = ' checked="checked"';
+                $this->_formShows[$new_column_count]
+                    = $_POST['criteriaShow'][$column_index];
+            } else {
+                $checked_options = '';
+            }
+            $html_output .= '<td class="center">';
+            $html_output .= '<input type="checkbox"'
+                . ' name="criteriaShow[' . $new_column_count . ']"'
+                . $checked_options . '>';
+            $html_output .= '</td>';
+            $new_column_count++;
+        } // end for
+        $html_output .= '</tr>';
+        return $html_output;
+    }
+
+    /**
+     * Provides search form's row containing criteria Inputboxes
+     *
+     * @return string HTML for search table's row
+     */
+    private function _getCriteriaInputboxRow()
+    {
+        $html_output = '<tr class="noclick">';
+        $html_output .= '<th>' . __('Criteria:') . '</th>';
+        $new_column_count = 0;
+        for ($column_index = 0; $column_index < $this->_criteria_column_count; $column_index++) {
+            if (! empty($this->_criteriaColumnInsert)
+                && isset($this->_criteriaColumnInsert[$column_index])
+                && $this->_criteriaColumnInsert[$column_index] == 'on'
+            ) {
+                $html_output .= '<td class="center">';
+                $html_output .= '<input type="text"'
+                    . ' name="criteria[' . $new_column_count . ']"'
+                    . ' class="textfield"'
+                    . ' style="width: ' . $this->_realwidth . '"'
+                    . ' size="20">';
+                $html_output .= '</td>';
+                $new_column_count++;
+            } // end if
+            if (! empty($this->_criteriaColumnDelete)
+                && isset($this->_criteriaColumnDelete[$column_index])
+                && $this->_criteriaColumnDelete[$column_index] == 'on'
+            ) {
+                continue;
+            }
+            $tmp_criteria = '';
+            if (isset($this->_criteria[$column_index])) {
+                $tmp_criteria = $this->_criteria[$column_index];
+            }
+            if ((empty($this->_prev_criteria)
+                || ! isset($this->_prev_criteria[$column_index]))
+                || $this->_prev_criteria[$column_index] != htmlspecialchars($tmp_criteria)
+            ) {
+                $this->_formCriterions[$new_column_count] = $tmp_criteria;
+            } else {
+                $this->_formCriterions[$new_column_count]
+                    = $this->_prev_criteria[$column_index];
+            }
+            $html_output .= '<td class="center">';
+            $html_output .= '<input type="hidden"'
+                . ' name="prev_criteria[' . $new_column_count . ']"'
+                . ' value="'
+                . htmlspecialchars($this->_formCriterions[$new_column_count])
+                . '">';
+            $html_output .= '<input type="text"'
+                . ' name="criteria[' . $new_column_count . ']"'
+                . ' value="' . htmlspecialchars($tmp_criteria) . '"'
+                . ' class="textfield"'
+                . ' style="width: ' . $this->_realwidth . '"'
+                . ' size="20">';
+            $html_output .= '</td>';
+            $new_column_count++;
+        } // end for
+        $html_output .= '</tr>';
+        return $html_output;
+    }
+
+    /**
+     * Provides footer options for adding/deleting row/columns
+     *
+     * @param string $type Whether row or column
+     *
+     * @return string HTML for footer options
+     */
+    private function _getFootersOptions($type)
+    {
+        return $this->template->render('database/qbe/footer_options', [
+            'type' => $type,
+        ]);
+    }
+
+    /**
+     * Provides search form table's footer options
+     *
+     * @return string HTML for table footer
+     */
+    private function _getTableFooters()
+    {
+        $html_output = '<fieldset class="tblFooters">';
+        $html_output .= $this->_getFootersOptions("row");
+        $html_output .= $this->_getFootersOptions("column");
+        $html_output .= '<div class="floatleft">';
+        $html_output .= '<input class="btn btn-secondary" type="submit" name="modify"'
+            . ' value="' . __('Update Query') . '">';
+        $html_output .= '</div>';
+        $html_output .= '</fieldset>';
+        return $html_output;
+    }
+
+    /**
+     * Provides a select list of database tables
+     *
+     * @return string HTML for table select list
+     */
+    private function _getTablesList()
+    {
+        $html_output = '<div class="floatleft width100">';
+        $html_output .= '<fieldset>';
+        $html_output .= '<legend>' . __('Use Tables') . '</legend>';
+        // Build the options list for each table name
+        $options = '';
+        $numTableListOptions = 0;
+        foreach ($this->_criteriaTables as $key => $val) {
+            $options .= '<option value="' . htmlspecialchars($key) . '"' . $val . '>'
+                . str_replace(' ', '&nbsp;', htmlspecialchars($key)) . '</option>';
+            $numTableListOptions++;
+        }
+        $html_output .= '<select name="TableList[]"'
+            . ' multiple="multiple" id="listTable"'
+            . ' size="' . ($numTableListOptions > 30 ? '15' : '7') . '">';
+        $html_output .= $options;
+        $html_output .= '</select>';
+        $html_output .= '</fieldset>';
+        $html_output .= '<fieldset class="tblFooters">';
+        $html_output .= '<input class="btn btn-secondary" type="submit" name="modify" value="'
+            . __('Update Query') . '">';
+        $html_output .= '</fieldset>';
+        $html_output .= '</div>';
+        return $html_output;
+    }
+
+    /**
+     * Provides And/Or modification cell along with Insert/Delete options
+     * (For modifying search form's table columns)
+     *
+     * @param integer    $column_number Column Number (0,1,2) or more
+     * @param array|null $selected      Selected criteria column name
+     * @param bool       $last_column   Whether this is the last column
+     *
+     * @return string HTML for modification cell
+     */
+    private function _getAndOrColCell(
+        $column_number,
+        $selected = null,
+        $last_column = false
+    ) {
+        $html_output = '<td class="center">';
+        if (! $last_column) {
+            $html_output .= '<strong>' . __('Or:') . '</strong>';
+            $html_output .= '<input type="radio"'
+                . ' name="criteriaAndOrColumn[' . $column_number . ']"'
+                . ' value="or"' . ($selected['or'] ?? '') . '>';
+            $html_output .= '&nbsp;&nbsp;<strong>' . __('And:') . '</strong>';
+            $html_output .= '<input type="radio"'
+                . ' name="criteriaAndOrColumn[' . $column_number . ']"'
+                . ' value="and"' . ($selected['and'] ?? '') . '>';
+        }
+        $html_output .= '<br>' . __('Ins');
+        $html_output .= '<input type="checkbox"'
+            . ' name="criteriaColumnInsert[' . $column_number . ']">';
+        $html_output .= '&nbsp;&nbsp;' . __('Del');
+        $html_output .= '<input type="checkbox"'
+            . ' name="criteriaColumnDelete[' . $column_number . ']">';
+        $html_output .= '</td>';
+        return $html_output;
+    }
+
+    /**
+     * Provides search form's row containing column modifications options
+     * (For modifying search form's table columns)
+     *
+     * @return string HTML for search table's row
+     */
+    private function _getModifyColumnsRow()
+    {
+        $html_output = '<tr class="noclick">';
+        $html_output .= '<th>' . __('Modify:') . '</th>';
+        $new_column_count = 0;
+        for ($column_index = 0; $column_index < $this->_criteria_column_count; $column_index++) {
+            if (! empty($this->_criteriaColumnInsert)
+                && isset($this->_criteriaColumnInsert[$column_index])
+                && $this->_criteriaColumnInsert[$column_index] == 'on'
+            ) {
+                $html_output .= $this->_getAndOrColCell($new_column_count);
+                $new_column_count++;
+            } // end if
+
+            if (! empty($this->_criteriaColumnDelete)
+                && isset($this->_criteriaColumnDelete[$column_index])
+                && $this->_criteriaColumnDelete[$column_index] == 'on'
+            ) {
+                continue;
+            }
+
+            if (isset($this->_criteriaAndOrColumn[$column_index])) {
+                $this->_formAndOrCols[$new_column_count]
+                    = $this->_criteriaAndOrColumn[$column_index];
+            }
+            $checked_options = [];
+            if (isset($this->_criteriaAndOrColumn[$column_index])
+                && $this->_criteriaAndOrColumn[$column_index] == 'or'
+            ) {
+                $checked_options['or']  = ' checked="checked"';
+                $checked_options['and'] = '';
+            } else {
+                $checked_options['and'] = ' checked="checked"';
+                $checked_options['or']  = '';
+            }
+            $html_output .= $this->_getAndOrColCell(
+                $new_column_count,
+                $checked_options,
+                $column_index + 1 == $this->_criteria_column_count
+            );
+            $new_column_count++;
+        } // end for
+        $html_output .= '</tr>';
+        return $html_output;
+    }
+
+    /**
+     * Provides Insert/Delete options for criteria inputbox
+     * with AND/OR relationship modification options
+     *
+     * @param integer $row_index       Number of criteria row
+     * @param array   $checked_options If checked
+     *
+     * @return string HTML
+     */
+    private function _getInsDelAndOrCell($row_index, array $checked_options)
+    {
+        $html_output = '<td class="value nowrap">';
+        $html_output .= '<!-- Row controls -->';
+        $html_output .= '<table class="nospacing nopadding">';
+        $html_output .= '<tr>';
+        $html_output .= '<td class="value nowrap">';
+        $html_output .= '<small>' . __('Ins:') . '</small>';
+        $html_output .= '<input type="checkbox"'
+            . ' name="criteriaRowInsert[' . $row_index . ']">';
+        $html_output .= '</td>';
+        $html_output .= '<td class="value">';
+        $html_output .= '<strong>' . __('And:') . '</strong>';
+        $html_output .= '</td>';
+        $html_output .= '<td>';
+        $html_output .= '<input type="radio"'
+            . ' name="criteriaAndOrRow[' . $row_index . ']" value="and"'
+            . $checked_options['and'] . '>';
+        $html_output .= '</td>';
+        $html_output .= '</tr>';
+        $html_output .= '<tr>';
+        $html_output .= '<td class="value nowrap">';
+        $html_output .= '<small>' . __('Del:') . '</small>';
+        $html_output .= '<input type="checkbox"'
+            . ' name="criteriaRowDelete[' . $row_index . ']">';
+        $html_output .= '</td>';
+        $html_output .= '<td class="value">';
+        $html_output .= '<strong>' . __('Or:') . '</strong>';
+        $html_output .= '</td>';
+        $html_output .= '<td>';
+        $html_output .= '<input type="radio"'
+            . ' name="criteriaAndOrRow[' . $row_index . ']"'
+            . ' value="or"' . $checked_options['or'] . '>';
+        $html_output .= '</td>';
+        $html_output .= '</tr>';
+        $html_output .= '</table>';
+        $html_output .= '</td>';
+        return $html_output;
+    }
+
+    /**
+     * Provides rows for criteria inputbox Insert/Delete options
+     * with AND/OR relationship modification options
+     *
+     * @param integer $new_row_index New row index if rows are added/deleted
+     *
+     * @return string HTML table rows
+     */
+    private function _getInputboxRow($new_row_index)
+    {
+        $html_output = '';
+        $new_column_count = 0;
+        for ($column_index = 0; $column_index < $this->_criteria_column_count; $column_index++) {
+            if (! empty($this->_criteriaColumnInsert)
+                && isset($this->_criteriaColumnInsert[$column_index])
+                && $this->_criteriaColumnInsert[$column_index] == 'on'
+            ) {
+                $orFieldName = 'Or' . $new_row_index . '[' . $new_column_count . ']';
+                $html_output .= '<td class="center">';
+                $html_output .= '<input type="text"'
+                    . ' name="Or' . $orFieldName . '" class="textfield"'
+                    . ' style="width: ' . $this->_realwidth . '" size="20">';
+                $html_output .= '</td>';
+                $new_column_count++;
+            } // end if
+            if (! empty($this->_criteriaColumnDelete)
+                && isset($this->_criteriaColumnDelete[$column_index])
+                && $this->_criteriaColumnDelete[$column_index] == 'on'
+            ) {
+                continue;
+            }
+            $or = 'Or' . $new_row_index;
+            if (! empty($_POST[$or]) && isset($_POST[$or][$column_index])) {
+                $tmp_or = $_POST[$or][$column_index];
+            } else {
+                $tmp_or     = '';
+            }
+            $html_output .= '<td class="center">';
+            $html_output .= '<input type="text"'
+                . ' name="Or' . $new_row_index . '[' . $new_column_count . ']"'
+                . ' value="' . htmlspecialchars($tmp_or) . '" class="textfield"'
+                . ' style="width: ' . $this->_realwidth . '" size="20">';
+            $html_output .= '</td>';
+            if (! empty(${$or}) && isset(${$or}[$column_index])) {
+                $GLOBALS[${'cur' . $or}][$new_column_count]
+                    = ${$or}[$column_index];
+            }
+            $new_column_count++;
+        } // end for
+        return $html_output;
+    }
+
+    /**
+     * Provides rows for criteria inputbox Insert/Delete options
+     * with AND/OR relationship modification options
+     *
+     * @return string HTML table rows
+     */
+    private function _getInsDelAndOrCriteriaRows()
+    {
+        $html_output = '';
+        $new_row_count = 0;
+        $checked_options = [];
+        for ($row_index = 0; $row_index <= $this->_criteria_row_count; $row_index++) {
+            if (isset($this->_criteriaRowInsert[$row_index])
+                && $this->_criteriaRowInsert[$row_index] == 'on'
+            ) {
+                $checked_options['or']  = ' checked="checked"';
+                $checked_options['and'] = '';
+                $html_output .= '<tr class="noclick">';
+                $html_output .= $this->_getInsDelAndOrCell(
+                    $new_row_count,
+                    $checked_options
+                );
+                $html_output .= $this->_getInputboxRow(
+                    $new_row_count
+                );
+                $new_row_count++;
+                $html_output .= '</tr>';
+            } // end if
+            if (isset($this->_criteriaRowDelete[$row_index])
+                && $this->_criteriaRowDelete[$row_index] == 'on'
+            ) {
+                continue;
+            }
+            if (isset($this->_criteriaAndOrRow[$row_index])) {
+                $this->_formAndOrRows[$new_row_count]
+                    = $this->_criteriaAndOrRow[$row_index];
+            }
+            if (isset($this->_criteriaAndOrRow[$row_index])
+                && $this->_criteriaAndOrRow[$row_index] == 'and'
+            ) {
+                $checked_options['and'] =  ' checked="checked"';
+                $checked_options['or']  =  '';
+            } else {
+                $checked_options['or']  =  ' checked="checked"';
+                $checked_options['and'] =  '';
+            }
+            $html_output .= '<tr class="noclick">';
+            $html_output .= $this->_getInsDelAndOrCell(
+                $new_row_count,
+                $checked_options
+            );
+            $html_output .= $this->_getInputboxRow(
+                $new_row_count
+            );
+            $new_row_count++;
+            $html_output .= '</tr>';
+        } // end for
+        $this->_new_row_count = $new_row_count;
+        return $html_output;
+    }
+
+    /**
+     * Provides SELECT clause for building SQL query
+     *
+     * @return string Select clause
+     */
+    private function _getSelectClause()
+    {
+        $select_clause = '';
+        $select_clauses = [];
+        for ($column_index = 0; $column_index < $this->_criteria_column_count; $column_index++) {
+            if (! empty($this->_formColumns[$column_index])
+                && isset($this->_formShows[$column_index])
+                && $this->_formShows[$column_index] == 'on'
+            ) {
+                $select = $this->_formColumns[$column_index];
+                if (! empty($this->_formAliases[$column_index])) {
+                    $select .= " AS "
+                        . Util::backquote($this->_formAliases[$column_index]);
+                }
+                $select_clauses[] = $select;
+            }
+        } // end for
+        if (! empty($select_clauses)) {
+            $select_clause = 'SELECT '
+                . htmlspecialchars(implode(", ", $select_clauses)) . "\n";
+        }
+        return $select_clause;
+    }
+
+    /**
+     * Provides WHERE clause for building SQL query
+     *
+     * @return string Where clause
+     */
+    private function _getWhereClause()
+    {
+        $where_clause = '';
+        $criteria_cnt = 0;
+        for ($column_index = 0; $column_index < $this->_criteria_column_count; $column_index++) {
+            if (! empty($this->_formColumns[$column_index])
+                && ! empty($this->_formCriterions[$column_index])
+                && $column_index
+                && isset($last_where)
+                && isset($this->_formAndOrCols)
+            ) {
+                $where_clause .= ' '
+                    . mb_strtoupper($this->_formAndOrCols[$last_where])
+                    . ' ';
+            }
+            if (! empty($this->_formColumns[$column_index])
+                && ! empty($this->_formCriterions[$column_index])
+            ) {
+                $where_clause .= '(' . $this->_formColumns[$column_index] . ' '
+                    . $this->_formCriterions[$column_index] . ')';
+                $last_where = $column_index;
+                $criteria_cnt++;
+            }
+        } // end for
+        if ($criteria_cnt > 1) {
+            $where_clause = '(' . $where_clause . ')';
+        }
+        // OR rows ${'cur' . $or}[$column_index]
+        if (! isset($this->_formAndOrRows)) {
+            $this->_formAndOrRows = [];
+        }
+        for ($row_index = 0; $row_index <= $this->_criteria_row_count; $row_index++) {
+            $criteria_cnt = 0;
+            $qry_orwhere = '';
+            $last_orwhere = '';
+            for ($column_index = 0; $column_index < $this->_criteria_column_count; $column_index++) {
+                if (! empty($this->_formColumns[$column_index])
+                    && ! empty($_POST['Or' . $row_index][$column_index])
+                    && $column_index
+                ) {
+                    $qry_orwhere .= ' '
+                        . mb_strtoupper(
+                            $this->_formAndOrCols[$last_orwhere]
+                        )
+                        . ' ';
+                }
+                if (! empty($this->_formColumns[$column_index])
+                    && ! empty($_POST['Or' . $row_index][$column_index])
+                ) {
+                    $qry_orwhere .= '(' . $this->_formColumns[$column_index]
+                        . ' '
+                        . $_POST['Or' . $row_index][$column_index]
+                        . ')';
+                    $last_orwhere = $column_index;
+                    $criteria_cnt++;
+                }
+            } // end for
+            if ($criteria_cnt > 1) {
+                $qry_orwhere      = '(' . $qry_orwhere . ')';
+            }
+            if (! empty($qry_orwhere)) {
+                $where_clause .= "\n"
+                    . mb_strtoupper(
+                        isset($this->_formAndOrRows[$row_index])
+                        ? $this->_formAndOrRows[$row_index] . ' '
+                        : ''
+                    )
+                    . $qry_orwhere;
+            } // end if
+        } // end for
+
+        if (! empty($where_clause) && $where_clause != '()') {
+            $where_clause = 'WHERE ' . htmlspecialchars($where_clause) . "\n";
+        } // end if
+        return $where_clause;
+    }
+
+    /**
+     * Provides ORDER BY clause for building SQL query
+     *
+     * @return string Order By clause
+     */
+    private function _getOrderByClause()
+    {
+        $orderby_clause = '';
+        $orderby_clauses = [];
+
+        // Create copy of instance variables
+        $columns = $this->_formColumns;
+        $sort = $this->_formSorts;
+        $sortOrder = $this->_formSortOrders;
+        if (! empty($sortOrder)
+            && count($sortOrder) == count($sort)
+            && count($sortOrder) == count($columns)
+        ) {
+            // Sort all three arrays based on sort order
+            array_multisort($sortOrder, $sort, $columns);
+        }
+
+        for ($column_index = 0; $column_index < $this->_criteria_column_count; $column_index++) {
+            // if all columns are chosen with * selector,
+            // then sorting isn't available
+            // Fix for Bug #570698
+            if (empty($columns[$column_index])
+                && empty($sort[$column_index])
+            ) {
+                continue;
+            }
+
+            if (mb_substr($columns[$column_index], -2) == '.*') {
+                continue;
+            }
+
+            if (! empty($sort[$column_index])) {
+                $orderby_clauses[] = $columns[$column_index] . ' '
+                    . $sort[$column_index];
+            }
+        } // end for
+        if (! empty($orderby_clauses)) {
+            $orderby_clause = 'ORDER BY '
+                . htmlspecialchars(implode(", ", $orderby_clauses)) . "\n";
+        }
+        return $orderby_clause;
+    }
+
+    /**
+     * Provides UNIQUE columns and INDEX columns present in criteria tables
+     *
+     * @param array $search_tables        Tables involved in the search
+     * @param array $search_columns       Columns involved in the search
+     * @param array $where_clause_columns Columns having criteria where clause
+     *
+     * @return array having UNIQUE and INDEX columns
+     */
+    private function _getIndexes(
+        array $search_tables,
+        array $search_columns,
+        array $where_clause_columns
+    ) {
+        $unique_columns = [];
+        $index_columns = [];
+
+        foreach ($search_tables as $table) {
+            $indexes = $this->dbi->getTableIndexes($this->_db, $table);
+            foreach ($indexes as $index) {
+                $column = $table . '.' . $index['Column_name'];
+                if (isset($search_columns[$column])) {
+                    if ($index['Non_unique'] == 0) {
+                        if (isset($where_clause_columns[$column])) {
+                            $unique_columns[$column] = 'Y';
+                        } else {
+                            $unique_columns[$column] = 'N';
+                        }
+                    } else {
+                        if (isset($where_clause_columns[$column])) {
+                            $index_columns[$column] = 'Y';
+                        } else {
+                            $index_columns[$column] = 'N';
+                        }
+                    }
+                }
+            } // end while (each index of a table)
+        } // end while (each table)
+
+        return [
+            'unique' => $unique_columns,
+            'index' => $index_columns,
+        ];
+    }
+
+    /**
+     * Provides UNIQUE columns and INDEX columns present in criteria tables
+     *
+     * @param array $search_tables        Tables involved in the search
+     * @param array $search_columns       Columns involved in the search
+     * @param array $where_clause_columns Columns having criteria where clause
+     *
+     * @return array having UNIQUE and INDEX columns
+     */
+    private function _getLeftJoinColumnCandidates(
+        array $search_tables,
+        array $search_columns,
+        array $where_clause_columns
+    ) {
+        $this->dbi->selectDb($this->_db);
+
+        // Get unique columns and index columns
+        $indexes = $this->_getIndexes(
+            $search_tables,
+            $search_columns,
+            $where_clause_columns
+        );
+        $unique_columns = $indexes['unique'];
+        $index_columns = $indexes['index'];
+
+        list($candidate_columns, $needsort)
+            = $this->_getLeftJoinColumnCandidatesBest(
+                $search_tables,
+                $where_clause_columns,
+                $unique_columns,
+                $index_columns
+            );
+
+        // If we came up with $unique_columns (very good) or $index_columns (still
+        // good) as $candidate_columns we want to check if we have any 'Y' there
+        // (that would mean that they were also found in the whereclauses
+        // which would be great). if yes, we take only those
+        if ($needsort != 1) {
+            return $candidate_columns;
+        }
+
+        $very_good = [];
+        $still_good = [];
+        foreach ($candidate_columns as $column => $is_where) {
+            $table = explode('.', $column);
+            $table = $table[0];
+            if ($is_where == 'Y') {
+                $very_good[$column] = $table;
+            } else {
+                $still_good[$column] = $table;
+            }
+        }
+        if (count($very_good) > 0) {
+            $candidate_columns = $very_good;
+            // Candidates restricted in index+where
+        } else {
+            $candidate_columns = $still_good;
+            // None of the candidates where in a where-clause
+        }
+
+        return $candidate_columns;
+    }
+
+    /**
+     * Provides the main table to form the LEFT JOIN clause
+     *
+     * @param array $search_tables        Tables involved in the search
+     * @param array $search_columns       Columns involved in the search
+     * @param array $where_clause_columns Columns having criteria where clause
+     * @param array $where_clause_tables  Tables having criteria where clause
+     *
+     * @return string table name
+     */
+    private function _getMasterTable(
+        array $search_tables,
+        array $search_columns,
+        array $where_clause_columns,
+        array $where_clause_tables
+    ) {
+        if (count($where_clause_tables) === 1) {
+            // If there is exactly one column that has a decent where-clause
+            // we will just use this
+            return key($where_clause_tables);
+        }
+
+        // Now let's find out which of the tables has an index
+        // (When the control user is the same as the normal user
+        // because he is using one of his databases as pmadb,
+        // the last db selected is not always the one where we need to work)
+        $candidate_columns = $this->_getLeftJoinColumnCandidates(
+            $search_tables,
+            $search_columns,
+            $where_clause_columns
+        );
+
+        // Generally, we need to display all the rows of foreign (referenced)
+        // table, whether they have any matching row in child table or not.
+        // So we select candidate tables which are foreign tables.
+        $foreign_tables = [];
+        foreach ($candidate_columns as $one_table) {
+            $foreigners = $this->relation->getForeigners($this->_db, $one_table);
+            foreach ($foreigners as $key => $foreigner) {
+                if ($key != 'foreign_keys_data') {
+                    if (in_array($foreigner['foreign_table'], $candidate_columns)) {
+                        $foreign_tables[$foreigner['foreign_table']]
+                            = $foreigner['foreign_table'];
+                    }
+                    continue;
+                }
+                foreach ($foreigner as $one_key) {
+                    if (in_array($one_key['ref_table_name'], $candidate_columns)) {
+                        $foreign_tables[$one_key['ref_table_name']]
+                            = $one_key['ref_table_name'];
+                    }
+                }
+            }
+        }
+        if (count($foreign_tables)) {
+            $candidate_columns = $foreign_tables;
+        }
+
+        // If our array of candidates has more than one member we'll just
+        // find the smallest table.
+        // Of course the actual query would be faster if we check for
+        // the Criteria which gives the smallest result set in its table,
+        // but it would take too much time to check this
+        if (! (count($candidate_columns) > 1)) {
+            // Only one single candidate
+            return reset($candidate_columns);
+        }
+
+        // Of course we only want to check each table once
+        $checked_tables = $candidate_columns;
+        $tsize = [];
+        $maxsize = -1;
+        $result = '';
+        foreach ($candidate_columns as $table) {
+            if ($checked_tables[$table] != 1) {
+                $_table = new Table($table, $this->_db);
+                $tsize[$table] = $_table->countRecords();
+                $checked_tables[$table] = 1;
+            }
+            if ($tsize[$table] > $maxsize) {
+                $maxsize = $tsize[$table];
+                $result = $table;
+            }
+        }
+        // Return largest table
+        return $result;
+    }
+
+    /**
+     * Provides columns and tables that have valid where clause criteria
+     *
+     * @return array
+     */
+    private function _getWhereClauseTablesAndColumns()
+    {
+        $where_clause_columns = [];
+        $where_clause_tables = [];
+
+        // Now we need all tables that we have in the where clause
+        for ($column_index = 0, $nb = count($this->_criteria); $column_index < $nb; $column_index++) {
+            $current_table = explode('.', $_POST['criteriaColumn'][$column_index]);
+            if (empty($current_table[0]) || empty($current_table[1])) {
+                continue;
+            } // end if
+            $table = str_replace('`', '', $current_table[0]);
+            $column = str_replace('`', '', $current_table[1]);
+            $column = $table . '.' . $column;
+            // Now we know that our array has the same numbers as $criteria
+            // we can check which of our columns has a where clause
+            if (! empty($this->_criteria[$column_index])) {
+                if (mb_substr($this->_criteria[$column_index], 0, 1) == '='
+                    || false !== stripos($this->_criteria[$column_index], 'is')
+                ) {
+                    $where_clause_columns[$column] = $column;
+                    $where_clause_tables[$table]  = $table;
+                }
+            } // end if
+        } // end for
+        return [
+            'where_clause_tables' => $where_clause_tables,
+            'where_clause_columns' => $where_clause_columns,
+        ];
+    }
+
+    /**
+     * Provides FROM clause for building SQL query
+     *
+     * @param array $formColumns List of selected columns in the form
+     *
+     * @return string FROM clause
+     */
+    private function _getFromClause(array $formColumns)
+    {
+        $from_clause = '';
+        if (empty($formColumns)) {
+            return $from_clause;
+        }
+
+        // Initialize some variables
+        $search_tables = $search_columns = [];
+
+        // We only start this if we have fields, otherwise it would be dumb
+        foreach ($formColumns as $value) {
+            $parts = explode('.', $value);
+            if (! empty($parts[0]) && ! empty($parts[1])) {
+                $table = str_replace('`', '', $parts[0]);
+                $search_tables[$table] = $table;
+                $search_columns[] = $table . '.' . str_replace(
+                    '`',
+                    '',
+                    $parts[1]
+                );
+            }
+        } // end while
+
+        // Create LEFT JOINS out of Relations
+        $from_clause = $this->_getJoinForFromClause(
+            $search_tables,
+            $search_columns
+        );
+
+        // In case relations are not defined, just generate the FROM clause
+        // from the list of tables, however we don't generate any JOIN
+        if (empty($from_clause)) {
+            // Create cartesian product
+            $from_clause = implode(
+                ', ',
+                array_map([Util::class, 'backquote'], $search_tables)
+            );
+        }
+
+        return $from_clause;
+    }
+
+    /**
+     * Formulates the WHERE clause by JOINing tables
+     *
+     * @param array $searchTables  Tables involved in the search
+     * @param array $searchColumns Columns involved in the search
+     *
+     * @return string table name
+     */
+    private function _getJoinForFromClause(array $searchTables, array $searchColumns)
+    {
+        // $relations[master_table][foreign_table] => clause
+        $relations = [];
+
+        // Fill $relations with inter table relationship data
+        foreach ($searchTables as $oneTable) {
+            $this->_loadRelationsForTable($relations, $oneTable);
+        }
+
+        // Get tables and columns with valid where clauses
+        $validWhereClauses = $this->_getWhereClauseTablesAndColumns();
+        $whereClauseTables = $validWhereClauses['where_clause_tables'];
+        $whereClauseColumns = $validWhereClauses['where_clause_columns'];
+
+        // Get master table
+        $master = $this->_getMasterTable(
+            $searchTables,
+            $searchColumns,
+            $whereClauseColumns,
+            $whereClauseTables
+        );
+
+        // Will include master tables and all tables that can be combined into
+        // a cluster by their relation
+        $finalized = [];
+        if (strlen($master) > 0) {
+            // Add master tables
+            $finalized[$master] = '';
+        }
+        // Fill the $finalized array with JOIN clauses for each table
+        $this->_fillJoinClauses($finalized, $relations, $searchTables);
+
+        // JOIN clause
+        $join = '';
+
+        // Tables that can not be combined with the table cluster
+        // which includes master table
+        $unfinalized = array_diff($searchTables, array_keys($finalized));
+        if (count($unfinalized) > 0) {
+            // We need to look for intermediary tables to JOIN unfinalized tables
+            // Heuristic to chose intermediary tables is to look for tables
+            // having relationships with unfinalized tables
+            foreach ($unfinalized as $oneTable) {
+                $references = $this->relation->getChildReferences($this->_db, $oneTable);
+                foreach ($references as $column => $columnReferences) {
+                    foreach ($columnReferences as $reference) {
+                        // Only from this schema
+                        if ($reference['table_schema'] != $this->_db) {
+                            continue;
+                        }
+
+                        $table = $reference['table_name'];
+
+                        $this->_loadRelationsForTable($relations, $table);
+
+                        // Make copies
+                        $tempFinalized = $finalized;
+                        $tempSearchTables = $searchTables;
+                        $tempSearchTables[] = $table;
+
+                        // Try joining with the added table
+                        $this->_fillJoinClauses(
+                            $tempFinalized,
+                            $relations,
+                            $tempSearchTables
+                        );
+
+                        $tempUnfinalized = array_diff(
+                            $tempSearchTables,
+                            array_keys($tempFinalized)
+                        );
+                        // Take greedy approach.
+                        // If the unfinalized count drops we keep the new table
+                        // and switch temporary varibles with the original ones
+                        if (count($tempUnfinalized) < count($unfinalized)) {
+                            $finalized = $tempFinalized;
+                            $searchTables = $tempSearchTables;
+                        }
+
+                        // We are done if no unfinalized tables anymore
+                        if (count($tempUnfinalized) === 0) {
+                            break 3;
+                        }
+                    }
+                }
+            }
+
+            $unfinalized = array_diff($searchTables, array_keys($finalized));
+            // If there are still unfinalized tables
+            if (count($unfinalized) > 0) {
+                // Add these tables as cartesian product before joined tables
+                $join .= implode(
+                    ', ',
+                    array_map([Util::class, 'backquote'], $unfinalized)
+                );
+            }
+        }
+
+        $first = true;
+        // Add joined tables
+        foreach ($finalized as $table => $clause) {
+            if ($first) {
+                if (! empty($join)) {
+                    $join .= ", ";
+                }
+                $join .= Util::backquote($table);
+                $first = false;
+            } else {
+                $join .= "\n    LEFT JOIN " . Util::backquote(
+                    $table
+                ) . " ON " . $clause;
+            }
+        }
+
+        return $join;
+    }
+
+    /**
+     * Loads relations for a given table into the $relations array
+     *
+     * @param array  $relations array of relations
+     * @param string $oneTable  the table
+     *
+     * @return void
+     */
+    private function _loadRelationsForTable(array &$relations, $oneTable)
+    {
+        $relations[$oneTable] = [];
+
+        $foreigners = $this->relation->getForeigners($GLOBALS['db'], $oneTable);
+        foreach ($foreigners as $field => $foreigner) {
+            // Foreign keys data
+            if ($field == 'foreign_keys_data') {
+                foreach ($foreigner as $oneKey) {
+                    $clauses = [];
+                    // There may be multiple column relations
+                    foreach ($oneKey['index_list'] as $index => $oneField) {
+                        $clauses[]
+                            = Util::backquote($oneTable) . "."
+                            . Util::backquote($oneField) . " = "
+                            . Util::backquote($oneKey['ref_table_name']) . "."
+                            . Util::backquote($oneKey['ref_index_list'][$index]);
+                    }
+                    // Combine multiple column relations with AND
+                    $relations[$oneTable][$oneKey['ref_table_name']]
+                        = implode(" AND ", $clauses);
+                }
+            } else { // Internal relations
+                $relations[$oneTable][$foreigner['foreign_table']]
+                    = Util::backquote($oneTable) . "."
+                    . Util::backquote($field) . " = "
+                    . Util::backquote($foreigner['foreign_table']) . "."
+                    . Util::backquote($foreigner['foreign_field']);
+            }
+        }
+    }
+
+    /**
+     * Fills the $finalized arrays with JOIN clauses for each of the tables
+     *
+     * @param array $finalized    JOIN clauses for each table
+     * @param array $relations    Relations among tables
+     * @param array $searchTables Tables involved in the search
+     *
+     * @return void
+     */
+    private function _fillJoinClauses(array &$finalized, array $relations, array $searchTables)
+    {
+        while (true) {
+            $added = false;
+            foreach ($searchTables as $masterTable) {
+                $foreignData = $relations[$masterTable];
+                foreach ($foreignData as $foreignTable => $clause) {
+                    if (! isset($finalized[$masterTable])
+                        && isset($finalized[$foreignTable])
+                    ) {
+                        $finalized[$masterTable] = $clause;
+                        $added = true;
+                    } elseif (! isset($finalized[$foreignTable])
+                        && isset($finalized[$masterTable])
+                        && in_array($foreignTable, $searchTables)
+                    ) {
+                        $finalized[$foreignTable] = $clause;
+                        $added = true;
+                    }
+                    if ($added) {
+                        // We are done if all tables are in $finalized
+                        if (count($finalized) == count($searchTables)) {
+                            return;
+                        }
+                    }
+                }
+            }
+            // If no new tables were added during this iteration, break;
+            if (! $added) {
+                return;
+            }
+        }
+    }
+
+    /**
+     * Provides the generated SQL query
+     *
+     * @param array $formColumns List of selected columns in the form
+     *
+     * @return string SQL query
+     */
+    private function _getSQLQuery(array $formColumns)
+    {
+        $sql_query = '';
+        // get SELECT clause
+        $sql_query .= $this->_getSelectClause();
+        // get FROM clause
+        $from_clause = $this->_getFromClause($formColumns);
+        if (! empty($from_clause)) {
+            $sql_query .= 'FROM ' . htmlspecialchars($from_clause) . "\n";
+        }
+        // get WHERE clause
+        $sql_query .= $this->_getWhereClause();
+        // get ORDER BY clause
+        $sql_query .= $this->_getOrderByClause();
+        return $sql_query;
+    }
+
+    /**
+     * Provides the generated QBE form
+     *
+     * @return string QBE form
+     */
+    public function getSelectionForm()
+    {
+        $html_output = '<form action="db_qbe.php" method="post" id="formQBE" '
+            . 'class="lock-page">';
+        $html_output .= '<div class="width100">';
+        $html_output .= '<fieldset>';
+
+        if ($GLOBALS['cfgRelation']['savedsearcheswork']) {
+            $html_output .= $this->_getSavedSearchesField();
+        }
+
+        $html_output .= '<div class="responsivetable jsresponsive">';
+        $html_output .= '<table class="data" style="width: 100%;">';
+        // Get table's <tr> elements
+        $html_output .= $this->_getColumnNamesRow();
+        $html_output .= $this->_getColumnAliasRow();
+        $html_output .= $this->_getShowRow();
+        $html_output .= $this->_getSortRow();
+        $html_output .= $this->_getSortOrder();
+        $html_output .= $this->_getCriteriaInputboxRow();
+        $html_output .= $this->_getInsDelAndOrCriteriaRows();
+        $html_output .= $this->_getModifyColumnsRow();
+        $html_output .= '</table>';
+        $this->_new_row_count--;
+        $url_params = [];
+        $url_params['db'] = $this->_db;
+        $url_params['criteriaColumnCount'] = $this->_new_column_count;
+        $url_params['rows'] = $this->_new_row_count;
+        $html_output .= Url::getHiddenInputs($url_params);
+        $html_output .= '</div>';
+        $html_output .= '</fieldset>';
+        $html_output .= '</div>';
+        // get footers
+        $html_output .= $this->_getTableFooters();
+        // get tables select list
+        $html_output .= $this->_getTablesList();
+        $html_output .= '</form>';
+        $html_output .= '<form action="db_qbe.php" method="post" class="lock-page">';
+        $html_output .= Url::getHiddenInputs(['db' => $this->_db]);
+        // get SQL query
+        $html_output .= '<div class="floatleft desktop50">';
+        $html_output .= '<fieldset id="tblQbe">';
+        $html_output .= '<legend>'
+            . sprintf(
+                __('SQL query on database <b>%s</b>:'),
+                Util::getDbLink($this->_db)
+            );
+        $html_output .= '</legend>';
+        $text_dir = 'ltr';
+        $html_output .= '<textarea cols="80" name="sql_query" id="textSqlquery"'
+            . ' rows="' . (count($this->_criteriaTables) > 30 ? '15' : '7') . '"'
+            . ' dir="' . $text_dir . '">';
+
+        if (empty($this->_formColumns)) {
+            $this->_formColumns = [];
+        }
+        $html_output .= $this->_getSQLQuery($this->_formColumns);
+
+        $html_output .= '</textarea>';
+        $html_output .= '</fieldset>';
+        // displays form's footers
+        $html_output .= '<fieldset class="tblFooters" id="tblQbeFooters">';
+        $html_output .= '<input type="hidden" name="submit_sql" value="1">';
+        $html_output .= '<input class="btn btn-primary" type="submit" value="' . __('Submit Query') . '">';
+        $html_output .= '</fieldset>';
+        $html_output .= '</div>';
+        $html_output .= '</form>';
+        return $html_output;
+    }
+
+    /**
+     * Get fields to display
+     *
+     * @return string
+     */
+    private function _getSavedSearchesField()
+    {
+        $html_output = __('Saved bookmarked search:');
+        $html_output .= ' <select name="searchId" id="searchId">';
+        $html_output .= '<option value="">' . __('New bookmark') . '</option>';
+
+        $currentSearch = $this->_getCurrentSearch();
+        $currentSearchId = null;
+        $currentSearchName = null;
+        if (null != $currentSearch) {
+            $currentSearchId = $currentSearch->getId();
+            $currentSearchName = $currentSearch->getSearchName();
+        }
+
+        foreach ($this->_savedSearchList as $id => $name) {
+            $html_output .= '<option value="' . htmlspecialchars($id)
+                . '" ' . (
+                $id == $currentSearchId
+                    ? 'selected="selected" '
+                    : ''
+                )
+                . '>'
+                . htmlspecialchars($name)
+                . '</option>';
+        }
+        $html_output .= '</select>';
+        $html_output .= '<input type="text" name="searchName" id="searchName" '
+            . 'value="' . htmlspecialchars((string) $currentSearchName) . '">';
+        $html_output .= '<input type="hidden" name="action" id="action" value="">';
+        $html_output .= '<input class="btn btn-secondary" type="submit" name="saveSearch" id="saveSearch" '
+            . 'value="' . __('Create bookmark') . '">';
+        if (null !== $currentSearchId) {
+            $html_output .= '<input class="btn btn-secondary" type="submit" name="updateSearch" '
+                . 'id="updateSearch" value="' . __('Update bookmark') . '">';
+            $html_output .= '<input class="btn btn-secondary" type="submit" name="deleteSearch" '
+                . 'id="deleteSearch" value="' . __('Delete bookmark') . '">';
+        }
+
+        return $html_output;
+    }
+
+    /**
+     * Initialize _criteria_column_count
+     *
+     * @return int Previous number of columns
+     */
+    private function _initializeCriteriasCount(): int
+    {
+        // sets column count
+        $criteriaColumnCount = Core::ifSetOr(
+            $_POST['criteriaColumnCount'],
+            3,
+            'numeric'
+        );
+        $criteriaColumnAdd = Core::ifSetOr(
+            $_POST['criteriaColumnAdd'],
+            0,
+            'numeric'
+        );
+        $this->_criteria_column_count = max(
+            $criteriaColumnCount + $criteriaColumnAdd,
+            0
+        );
+
+        // sets row count
+        $rows = Core::ifSetOr($_POST['rows'], 0, 'numeric');
+        $criteriaRowAdd = Core::ifSetOr($_POST['criteriaRowAdd'], 0, 'numeric');
+        $this->_criteria_row_count = min(
+            100,
+            max($rows + $criteriaRowAdd, 0)
+        );
+
+        return (int) $criteriaColumnCount;
+    }
+
+    /**
+     * Get best
+     *
+     * @param array      $search_tables        Tables involved in the search
+     * @param array|null $where_clause_columns Columns with where clause
+     * @param array|null $unique_columns       Unique columns
+     * @param array|null $index_columns        Indexed columns
+     *
+     * @return array
+     */
+    private function _getLeftJoinColumnCandidatesBest(
+        array $search_tables,
+        ?array $where_clause_columns,
+        ?array $unique_columns,
+        ?array $index_columns
+    ) {
+        // now we want to find the best.
+        if (isset($unique_columns) && count($unique_columns) > 0) {
+            $candidate_columns = $unique_columns;
+            $needsort = 1;
+            return [
+                $candidate_columns,
+                $needsort,
+            ];
+        } elseif (isset($index_columns) && count($index_columns) > 0) {
+            $candidate_columns = $index_columns;
+            $needsort = 1;
+            return [
+                $candidate_columns,
+                $needsort,
+            ];
+        } elseif (isset($where_clause_columns) && count($where_clause_columns) > 0) {
+            $candidate_columns = $where_clause_columns;
+            $needsort = 0;
+            return [
+                $candidate_columns,
+                $needsort,
+            ];
+        }
+
+        $candidate_columns = $search_tables;
+        $needsort = 0;
+        return [
+            $candidate_columns,
+            $needsort,
+        ];
+    }
+}