一句sql查询
iddate note
12001-1-1test
22001-1-1sjd
32002-3-3fdfd
42002-3-3fdfd
52003-3-3fdfd
62004-3-3asa
72004-3-3fds
===>
date note
2001-1-1 null
2002-3-3fdfd
2003-3-3fdfd
2004-3-3null
[解决办法]
Select
Distinct
A.[date],
(Case When Exists(Select id From 表 Where [date] = A.[date] And note != A.note) Then Null Else A.note End) As note
From
表 A
[解决办法]
测试表Test
select distinct B.date, case when B.count> 1 then 'null '
else A.note
end note
from Test A,(select count(distinct note) count,date from Test group by date) B
where A.date=B.date
结果为
date note
2001-1-1 null
2001-1-2 fngd
2001-1-3 null
