求一条sql 一张表中有A B两个字段 判断A+B是否唯一。
如题 100分送上!
万分感谢
[解决办法]
DISTINCT后,还怎么判断唯一呢?
这种问题不应该用group by吗?
select a
[解决办法]
b ,count(*)
from tab
group by a
[解决办法]
b
--having count(*)>1 ---not unique
[解决办法]
SELECT A,B,COUNT(*)
FROM T
GROUP BY A,B
[解决办法]
支持3楼的,必须用group by 和 having count(1)>1
[解决办法]
select a,b,count(*) as cou
from [table]
group by a,b
having count(*)>1
select user_id
[解决办法]
qrbz ,count(*)
from askforleave
group by user_id
[解决办法]
qrbz
having count(*)>1;
select user_id,qrbz,count(*) as cou
from askforleave
group by user_id,qrbz
having count(*)>1;
create table tmp_zxf_01(A varchar2(10),B varchar2(10));
insert into tmp_zxf_01 values('A',null);
insert into tmp_zxf_01 values('A',null);
insert into tmp_zxf_01 values(null,'A');
insert into tmp_zxf_01 values('B',null);
insert into tmp_zxf_01 values(null,'B');
insert into tmp_zxf_01 values(null,'B');
insert into tmp_zxf_01 values('A','B');
insert into tmp_zxf_01 values('A','B');
select a,b
from (
select a,b,row_number()over(partition by a,b order by a) rid
from tmp_zxf_01
) where rid>1