#890994 by Berdir: Entity query tests fail on PostgreSQL.

1 files changed, 82 insertions, 0 deletions

diff --git a/includes/database/pgsql/query.inc b/includes/database/pgsql/query.inc
index 61c821801..2214d668a 100644
--- a/includes/database/pgsql/query.inc
+++ b/includes/database/pgsql/query.inc
@@ -217,4 +217,86 @@ class SelectQuery_pgsql extends SelectQuery {
     return $this;
   }
 
+  /**
+   * Overrides SelectQuery::orderBy().
+   *
+   * PostgreSQL adheres strictly to the SQL-92 standard and requires that when
+   * using DISTINCT or GROUP BY conditions, fields and expressions that are
+   * ordered on also need to be selected. This is a best effort implementation
+   * to handle the cases that can be automated by adding the field if it is not
+   * yet selected.
+   *
+   * @code
+   *   $query = db_select('node', 'n');
+   *   $query->join('node_revision', 'nr', 'n.vid = nr.vid');
+   *   $query
+   *     ->distinct()
+   *     ->fields('n')
+   *     ->orderBy('timestamp');
+   * @endcode
+   *
+   * In this query, it is not possible (without relying on the schema) to know
+   * whether timestamp belongs to node_revisions and needs to be added or
+   * belongs to node and is already selected. Queries like this will need to be
+   * corrected in the original query by adding an explicit call to
+   * SelectQuery::addField() or SelectQuery::fields().
+   *
+   * Since this has a small performance impact, both by the additional
+   * processing in this function and in the database that needs to return the
+   * additional fields, this is done as an override instead of implementing it
+   * directly in SelectQuery::orderBy().
+   */
+  public function orderBy($field, $direction = 'ASC') {
+    // Call parent function to order on this.
+    $return = parent::orderBy($field, $direction);
+
+    // If there is a table alias specified, split it up.
+    if (strpos($field, '.') !== FALSE) {
+      list($table, $table_field) = explode('.', $field);
+    }
+    // Figure out if the field has already been added.
+    foreach ($this->fields as $existing_field) {
+      if (!empty($table)) {
+        // If table alias is given, check if field and table exists.
+        if ($existing_field['table'] == $table && $existing_field['field'] == $table_field) {
+          return $return;
+        }
+      }
+      else {
+        // If there is no table, simply check if the field exists as a field or
+        // an aliased field.
+        if ($existing_field['alias'] == $field) {
+          return $return;
+        }
+      }
+    }
+
+    // Also check expression aliases.
+    foreach ($this->expressions as $expression) {
+      if ($expression['alias'] == $field) {
+        return $return;
+      }
+    }
+
+    // If a table loads all fields, it can not be added again. It would
+    // result in an ambigious alias error because that field would be loaded
+    // twice: Once through table_alias.* and once directly. If the field
+    // actually belongs to a different table, it must be added manually.
+    foreach ($this->tables as $table) {
+      if (!empty($table['all_fields'])) {
+        return $return;
+      }
+    }
+
+    // If $field contains an characters which are not allowed in a field name
+    // it is considered an expression, these can't be handeld automatically
+    // either.
+    if ($this->connection->escapeField($field) != $field) {
+      return $return;
+    }
+
+    // This is a case that can be handled automatically, add the field.
+    $this->addField(NULL, $field);
+    return $return;
+  }
 }