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inc/queryunion.class.php

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+<?php
+/**
+ * ---------------------------------------------------------------------
+ * GLPI - Gestionnaire Libre de Parc Informatique
+ * Copyright (C) 2015-2020 Teclib' and contributors.
+ *
+ * http://glpi-project.org
+ *
+ * based on GLPI - Gestionnaire Libre de Parc Informatique
+ * Copyright (C) 2003-2014 by the INDEPNET Development Team.
+ *
+ * ---------------------------------------------------------------------
+ *
+ * LICENSE
+ *
+ * This file is part of GLPI.
+ *
+ * GLPI is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GLPI is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GLPI. If not, see <http://www.gnu.org/licenses/>.
+ * ---------------------------------------------------------------------
+ */
+
+if (!defined('GLPI_ROOT')) {
+   die("Sorry. You can't access this file directly");
+}
+
+/**
+ * UNION query class
+**/
+class QueryUnion extends AbstractQuery {
+   private $queries = [];
+   private $distinct = false;
+
+   /**
+    * Create a sub query
+    *
+    * @param array   $queries  An array of queries to union. Either SubQuery objects
+    *                          or an array of criteria to build them.
+    *                          You can also add later using @see addQuery
+    * @param boolean $distinct Include duplicatesi or not. Turning on may has
+    *                          huge cost on queries performances.
+    * @param string  $alias    Union ALIAS. Defaults to null.
+    */
+   public function __construct(array $queries = [], $distinct = false, $alias = null) {
+      parent::__construct($alias);
+      $this->distinct = $distinct;
+
+      foreach ($queries as $query) {
+         $this->addQuery($query);
+      }
+   }
+
+   /**
+    * Add a query
+    *
+    * @param QuerySubQuery|array $query Either a SubQuery object
+    *                                   or an array of criteria to build it.
+    */
+   public function addQuery($query) {
+      if (!$query instanceof \QuerySubQuery) {
+         $query = new \QuerySubQuery($query);
+      }
+      $this->queries[] = $query;
+   }
+
+
+   /**
+    * Get queries
+    *
+    * @return array
+    */
+   public function getQueries() {
+      return $this->queries;
+   }
+
+   /**
+    *
+    * Get SQL query
+    *
+    * @return string
+    */
+   public function getQuery() {
+      global $DB;
+
+      $union_queries = $this->getQueries();
+      if (empty($union_queries
+      )) {
+         throw new \RuntimeException('Cannot build an empty union query');
+      }
+
+      $queries = [];
+      foreach ($union_queries as $uquery) {
+         $queries[] = $uquery->getQuery();
+      }
+
+      $keyword = 'UNION';
+      if (!$this->distinct) {
+         $keyword .= ' ALL';
+      }
+      $query = '(' . implode(" $keyword ", $queries) . ')';
+
+      $alias = $this->alias !== null
+         ? $this->alias
+         : 'union_' . md5($query);
+      $query .= ' AS ' . $DB->quoteName($alias);
+
+      return $query;
+   }
+}