/**
* Gets the SQL for a subquery and appends its parameters to current ones
*
* @param Query $query Query builder for the subquery
* @param array &$params Reference to parameters array
* @return string Subquery SQL
*/
protected function subquery($query, &$params)
{
$query->setIsRoot(false);
$query->setParent($this);
$query = $query->query();
$params = array_merge($params, $query[1]);
return "({$query[0]}) ";
}
