Issue #2183417 by kgoel, alimac: In Sql Rename Views properties to core standards.

core/modules/views/src/Plugin/views/query/QueryPluginBase.php

@@ -175,7 +175,7 @@ public function setWhereGroup($type = 'AND', $group = NULL, $where = 'where') {
    *   Either 'AND' or 'OR'
    */
   public function setGroupOperator($type = 'AND') {
-    $this->group_operator = strtoupper($type);
+    $this->groupOperator = strtoupper($type);
   }
 
   /**