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

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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：

UPDATE bus_clew SET clew_status = '3' WHERE

id IN (

SELECT

c.id

FROM

bus_clew c,

bus_clew_keeper k

WHERE

c.id = k.clew_id

AND c.clew_status = 0

AND c.is_del = 0

AND EXISTS (

SELECT

1

FROM

bus_clew_track t

WHERE

t.clew_id = c.id

AND t.keeper_id = k.keeper_id

AND t.is_del = 0

)

);

 

要改成下面：

UPDATE bus_clew SET clew_status = '3' WHERE

id IN (

 

select c1.id from (

SELECT

c.id

FROM

bus_clew c,

bus_clew_keeper k

WHERE

c.id = k.clew_id

AND c.clew_status = 0

AND c.is_del = 0

AND EXISTS (

SELECT

1

FROM

bus_clew_track t

WHERE

t.clew_id = c.id

AND t.keeper_id = k.keeper_id

AND t.is_del = 0

)) c1

);

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。