diff -u b/includes/entity.inc b/includes/entity.inc
--- b/includes/entity.inc
+++ b/includes/entity.inc
@@ -190,8 +190,7 @@
 
     // Ensure integer revision ID is valid.
     if (!empty($revision_id)) {
-      $revision_ids = array($revision_id);
-      $this->cleanIds($revision_ids);
+      $revision_id = $this->cleanRevisionId($revision_id);
     }
 
     // Load any remaining entities from the database. This is the case if $ids
@@ -254,13 +253,31 @@
         $ids = array_map('intval', $ids);
       }
     }
+  }
+
+  /**
+   * Ensures integer entity revision ID is valid.
+   *
+   * The identifier sanitization provided by this method has been introduced
+   * as Drupal used to rely on the database to facilitate this, which worked
+   * correctly with MySQL but led to errors with other DBMS such as PostgreSQL.
+   *
+   * @param int $id
+   *   The entity ID revision to verify. Non-integer ID are removed from this
+   *   array if the entity type requires ID to be integer.
+   *
+   * @return int|bool
+   *   The passed in ID if it is valid, FALSE otherwise.
+   */
+  protected function cleanRevisionId($id) {
+    $entity_info = entity_get_info($this->entityType);
     if (isset($entity_info['revision table field types'])) {
       $id_type = $entity_info['revision table field types'][$this->idKey];
       if ($id_type == 'serial' || $id_type == 'int') {
-        $ids = array_filter($ids, array($this, 'filterId'));
-        $ids = array_map('intval', $ids);
+        return $this->filterId($id) ? $id : FALSE;
       }
     }
+    return $id;
   }
 
   /**
@@ -300,6 +317,11 @@
 
     $query->addTag($this->entityType . '_load_multiple');
 
+    // Ensure integer revision ID is valid.
+    if (!empty($revision_id)) {
+      $revision_id = $this->cleanRevisionId($revision_id);
+    }
+
     if ($revision_id) {
       $query->join($this->revisionTable, 'revision', "revision.{$this->idKey} = base.{$this->idKey} AND revision.{$this->revisionKey} = :revisionId", array(':revisionId' => $revision_id));
     }