2个查询 难度
一
a表
id1,id2,s
id1,id2 2个是主键
b表
id1,id2,s1
id1,id2 2个是主键
要求写一个SQL语句删除a表中id1,id2和b表中id1,id2相同的记录！
二
a表
id1,s1
b表
id1,s2
要求对a表id1字段=b表id1时候，将a表s1设置为b表根据id1分组sum(s2)值，
即select id1,sum(s2) from b group by id1
[解决办法]
up
[解决办法]
delete from a
where exists (select 'Z ' from b where a.id1=b.id1 and a.id2=b.id2)
update a
set s1=(select sum(s2) from b where a.id1=b.id1 group by b.id1)
[解决办法]
delete a
from a
where exists(select 1 from b where b.id1 = a.id1 and b.id2 = a.id2
update c
set s1 = temp.curSum
from c, (select id1, sum(s2) as curSum from d group by id1)temp
where c.id1 = temp.id1
