You can't specify target table '表名' for update in FROM clause

翻译为：不能先select出同一表中的某些值，再update这个表(在同一语句中)

错误写法：

UPDATE snc_visualpanel_tree
    SET node_type = '1'  WHERE   parentid IN (
       SELECT(
	 		SELECT   flid
			FROM  snc_visualpanel_tree
			WHERE   type = 1  AND parentid = '1'
			)
	);

正确写法：

UPDATE snc_visualpanel_tree
SET node_type = '1'
 WHERE  parentid IN (
		SELECT  aa.flid   FROM
			(
				SELECT   flid   FROM
					snc_visualpanel_tree
				WHERE   type = 1  AND parentid = '1'
			) aa
	);

也就是说：把结果集当作一个表，自我查询一遍

格式为：SELECT a.StudentResult  FROM    (结果集)a