public function innerJoin($table, $alias_or_cond, $cond = null) {
		if (is_null($cond))
			$this->joins[] = new JoinClause(JoinClause::INNER_JOIN, $table, null, $alias_or_cond);
		else
			$this->joins[] = new JoinClause(JoinClause::INNER_JOIN, $table, $alias_or_cond, $cond);
		return $this;
	}