/** Throws a validation error if a DISTINCT or ALL quantifier is present but not allowed. */
 protected void validateQuantifier(SqlValidator validator, SqlCall call) {
   if ((null != call.getFunctionQuantifier()) && !isQuantifierAllowed()) {
     throw validator.newValidationError(
         call.getFunctionQuantifier(),
         EigenbaseResource.instance()
             .FunctionQuantifierNotAllowed
             .ex(call.getOperator().getName()));
   }
 }