MySQL的update from和多表更新  

在MySQL里,不可以修改同一个表并使用SELECＴ语句.详情查看http://dev.mysql.com/doc/mysql/en/UPDATE.html

可以选用JOIN来实现,例证如下

用SELECT的原语句:

update spms.user

set DirectReport=(select DirectReport from spms.user where UserName='%s')

where UserName in (select UserName from spms.user where DirectReport='%s')

 

选用JOIN来实现的语句:

update spms.user as u1

inner join spms.user as u2 on u1.DirectReport= u2.UserName

set u1.DirectReport=u2.DirectReport where u2.UserName='%s'

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