MySQL之You can't specify target table for update in FROM clause解决办法
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MySQL中You can't specify target table for update in FROM clause错误的意思是说,不能先select出同一表中的某些值,再update这个表(在同一语句中)。 例如下面这个sql:
delete from tbl where id in
(
select max(id) from tbl a where EXISTS
(
select 1 from tbl b where a.tac=b.tac group by tac HAVING count(1)>1
)
group by tac
)
也就是说将select出的结果再通过中间表select一遍,这样就规避了错误。注意,这个问题只出现于mysql,mssql和Oracle不会出现此问题。
delete from tbl where id in
(
select a.id from
(
select max(id) id from tbl a where EXISTS
(
select 1 from tbl b where a.tac=b.tac group by tac HAVING count(1)>1
)
group by tac
) a
)
UPDATE t_user_asset SET f_cashAmount =
(
SELECT ub.cashAmount FROM
(
SELECT (ua.f_cashAmount+50000) cashAmount FROM t_user_asset ua WHERE ua.f_userId = 290
) ub
)
WHERE f_userId = 290
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