SQL编程问题

来源：百度知道编辑：UC知道时间：2024/05/21 19:33:50

现在有A、B、C三个表，B、C有外键b、c分别连到A的a上，现在要删除A表中的某行，要判断B、C中是否有关联的，有的就提示不能删除，没有的就删除这条记录，请大家帮帮忙，看看怎么做？

delete without alert:
DELETE FROM A
WHERE NOT EXISTS(SELECT * FROM B WHERE (B.Aid = A.Aid))
AND NOT EXISTS(SELECT * FROM C WHERE (C.Aid = A.Aid))

just check:
DECLARE @aid int
IF (EXISTS(SELECT * FROM B WHERE (B.Aid = @aid))
OR EXISTS(SELECT * FROM C WHERE (C.Aid = @aid)))
--ALERT
ELSE
DELETE FROM A
WHERE (A.Aid = @aid)

DELETE A WHERE aid = '*' and aid NOT IN(select A.aid FROM B,C,A where b.bid = a.aid and c.cid = a.aid)大概思路是这样如果和你说的这个程序连接包括消息提示可以另外写一个sql返回一个标记

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