MySql:You can not specify target table for update in FROM clause錯誤

字面意思是：不能在FROM子句中爲更新指定目標表“area”。咋一看可能有點懵，其實意思是就是不能直接在子查詢裏查詢要修改的這張表。

引發報錯的SQL:

UPDATE area
SET state = 0
WHERE
 id IN (
		SELECT
			ar2.id
		FROM
			area AS ar1
		INNER JOIN area AS ar2 ON ar2.parent_id = ar1.id
		WHERE
			ar1.parent_id = '110000'
		OR ar1.id = '110000'
		OR ar2.parent_id = '110000'
	)
OR id = '110000'

修改後的版本：

UPDATE area
SET state = 0
WHERE
	id IN (
		SELECT
			id
		FROM
			(
				SELECT
					ar2.id
				FROM
					area AS ar1
				INNER JOIN area AS ar2 ON ar2.parent_id = ar1.id
				WHERE
					ar1.parent_id = '110000'
				OR ar1.id = '110000'
				OR ar2.parent_id = '110000'
			) childs
	)
OR id = '110000';

很簡單的道理，多給他嵌套一層，不讓他直接關聯就行了，舉一反三，刪除時報這個錯也是同樣的道理。