求一对多查询语句写法
表A 记录 aa bb
表B 记录 cc dd
aa和cc一对多,
查询 select bb,dd
表A不要出现多次,就是表A对应的表B只要第一条
[解决办法]
Select
A.bb,
Max(B.dd) As dd
From
A
Left Join
B
On A.aa = B.cc
Group By
A.bb
[解决办法]
select bb,(select top 1 dd from b where b.cc=a.aa) as dd from a
[解决办法]
select bb,dd
from 表A,(select top 1 cc,dd from 表B)表B
where 表A.aa=表B.cc
[解决办法]
select bb,dd from (select a.*,b.* from aa,bb where a.aa=b.cc) t group by bb
[解决办法]
更正一下:
select bb,min(dd) from (select a.*,b.* from aa,bb where a.aa=b.cc) t group by bb
