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Differences Between: [Versions 400 and 401]

   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  declare(strict_types=1);
  18  
  19  namespace core_reportbuilder\local\aggregation;
  20  
  21  use lang_string;
  22  use core_reportbuilder\local\helpers\database;
  23  
  24  /**
  25   * Column group concatenation distinct aggregation type
  26   *
  27   * @package     core_reportbuilder
  28   * @copyright   2021 Paul Holden <paulh@moodle.com>
  29   * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  30   */
  31  class groupconcatdistinct extends groupconcat {
  32  
  33      /**
  34       * Return aggregation name
  35       *
  36       * @return lang_string
  37       */
  38      public static function get_name(): lang_string {
  39          return new lang_string('aggregationgroupconcatdistinct', 'core_reportbuilder');
  40      }
  41  
  42      /**
  43       * This aggregation can be performed on all non-timestamp columns in MySQL, Postgres and Oracle only
  44       *
  45       * @param int $columntype
  46       * @return bool
  47       */
  48      public static function compatible(int $columntype): bool {
  49          global $DB;
  50  
  51          $dbsupportedtype = in_array($DB->get_dbfamily(), [
  52              'mysql',
  53              'postgres',
  54              'oracle',
  55          ]);
  56  
  57          return $dbsupportedtype && parent::compatible($columntype);
  58      }
  59  
  60      /**
  61       * Return the aggregated field SQL
  62       *
  63       * @param string $field
  64       * @param int $columntype
  65       * @return string
  66       */
  67      public static function get_field_sql(string $field, int $columntype): string {
  68          global $DB;
  69  
  70          $fieldsort = database::sql_group_concat_sort($field);
  71  
  72          // Postgres handles group concatenation differently in that it requires the expression to be cast to char, so we can't
  73          // simply pass "DISTINCT {$field}" to the {@see \moodle_database::sql_group_concat} method in all cases.
  74          if ($DB->get_dbfamily() === 'postgres') {
  75              $field = $DB->sql_cast_to_char($field);
  76              if ($fieldsort !== '') {
  77                  $fieldsort = "ORDER BY {$fieldsort}";
  78              }
  79  
  80              return "STRING_AGG(DISTINCT {$field}, '" . self::FIELD_VALUE_DELIMETER . "' {$fieldsort})";
  81          } else {
  82              return $DB->sql_group_concat("DISTINCT {$field}", self::FIELD_VALUE_DELIMETER, $fieldsort);
  83          }
  84      }
  85  }