Question

我有两张桌子：

users user_id, status列
changes user_id, type列

我想从changes删除一行，如果type = 5，则设置：

users.status = NULL Where users.user_id = changes.user_id

我该怎么做？

Answer 1

试试这个：

-- table variable to store deleted changes
declare @deleted_changes table(user_id int, [type] int);

-- saving info from deleted changes into temp table
delete from changes 
output deleted.user_id, deleted.[type] into @deleted_changes;
-- where [some condition]

-- updating users only if corresponding changes with type = 5 were deleted
update users
set status = null
where user_id in (select user_id from @deleted_changes where [type] = 5);

Answer 2

对于DELETE，你的意思是......

DELETE FROM Changes WHERE type = 5

尝试以下更新....

UPDATE  u
SET     u.status = NULL
FROM    users u
        INNER JOIN changes c ON u.user_id = c.user_id

如何更新从另一个表中删除的行？

2 个答案: