A
----
id name Bid
1 A1 1
2 A2 1
3 A3 2
4 A4 2
5 A5 2B
----
Bid name Cid
1 B1 1
2 B2 1
3 B3 2
4 B4 2
5 B5 2A 的 Bid 对应 B 的 Bid
select * from A where Bid in (select Bid from B where Cid = 1)
现在知道 A 的Bid = 1,求出 B 的Cid = 多少?
可以看出Cid = 1,但我想用一条sql语句求出来,如何写?
----
id name Bid
1 A1 1
2 A2 1
3 A3 2
4 A4 2
5 A5 2B
----
Bid name Cid
1 B1 1
2 B2 1
3 B3 2
4 B4 2
5 B5 2A 的 Bid 对应 B 的 Bid
select * from A where Bid in (select Bid from B where Cid = 1)
现在知道 A 的Bid = 1,求出 B 的Cid = 多少?
可以看出Cid = 1,但我想用一条sql语句求出来,如何写?
?
insert A select 1, 'A1', 1
union all select 2, 'A2', 1
union all select 3, 'A3', 2
union all select 4, 'A4', 2
union all select 5, 'A5', 2create table B(Bid int, name char(2), Cid int)
insert B select 1, 'B1', 1
union all select 2, 'B2', 1
union all select 3, 'B3', 2
union all select 4, 'B4', 2
union all select 5, 'B5', 2select * from A, B
where A.Bid=B.Bid and A.Bid=1--result
id name Bid Bid name Cid
----------- ---- ----------- ----------- ---- -----------
1 A1 1 1 B1 1
2 A2 1 1 B1 1(2 row(s) affected)