sql - 将 SELECT 转换为更新语句

Question

SELECT t1.status, t3.guid, t3.objectID
FROM Table1 t1, Table2 t2, Table3 t3
WHERE t2.ID = t3.ID
   AND t1.ID = t2.ID
   AND t3.Guid IN ('', '', '')

如何将其转换为更新语句，在其中设置 t1.status = 1 ?

Answer 1

我首先将其转换为使用连接而不是“经典连接”:

select t1.status, t3.guid, t3.objectID
from Table1 t1
inner join Table2 t2 on t2.ID = t1.ID
inner join Table3 t3 on t3.ID = t2.ID
where t3.Guid in ('', '', '')

然后你可以撕掉 select 语句并在它上面加上一个 update 和 set 语句:

update t1
set status = 1
from Table1 t1
inner join Table2 t2 on t2.ID = t1.ID
inner join Table3 t3 on t3.ID = t2.ID
where t3.Guid in ('', '', '')