public function extendWhere($outerGlue, $conditions, $innerGlue = 'AND')
	{
		// Replace the current WHERE with a new one which has the old one as an unnamed child.
		$this->where = new Query\QueryElement('WHERE', $this->where->setName('()'), " $outerGlue ");

		// Append the new conditions as a new unnamed child.
		$this->where->append(new Query\QueryElement('()', $conditions, " $innerGlue "));

		return $this;
	}