sql 高手来看一下

[huwei12345]

假如有如下表
ID A B
1 a1 b1
2 a1 b1
3 a2 b2

我想得到不重复的 a 和 b 的 随便一个 id 列
如 1,3 或者 2,3都行 ，高手有什么办法？这个id 随便取一个就好了

[cpp2017]

1,3 2,3是两个id

[cpp2017]

只这个意思么?


select (select top 1 id from TB where a=AA.a and b= aa.b) as id ,AA.* FROM

(
select distinct a,b from tb ) AS AA

[conan304]

select * from tb
where not exists(select 1 from tb where tb.a=a and tb.b=b and tb.id<id)

[wonture]

啥意思……

[dd__dd]

select (select top 1 id from TB where a=AA.a and b= aa.b) as id ,AA.* FROM

(
select distinct a,b from tb ) AS AA
----------------------------------
应该是这个意思吧

[gjw_8888]

數據庫版裡有很多這樣的答案lz可以去找找

[xiaoqhuang]

select min(id) as id, AA,BB from tb group by A,B

[阿非]

select min([ID]) from tableName group by [A],[B]

[xfreyes]

按上面方法应该可以实现，但这样的库设计明显有缺陷。。。
建议改改表结构

[zzxap]

ID A B
1 a1 b1
2 a1 b1
3 a2 b2
[code=SQL]
SELECT * FROM TABNLE A WHERE EXISTS ( SELECT TOP 1 ID FROM TABLE WHERE A=A.A AND B=A.B )

[/CODE]

[iabswfg858]

SELECT A，B FROM TABLE GROUP BY A,B

[huwei12345]

对哦，min 或者 max 就可以实现了，哈哈