select distinct * from 表
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select id,a,max(isnull(b,'')) b from table group by id,a
create table #hhh
(id int,
a varchar(100),
b varchar(100)
)
insert into #hhh values ('1','a1','E')
insert into #hhh values ('2','a1','')
insert into #hhh values ('3','a2','E')
insert into #hhh values ('4','a3','')
--select top 1 id,a,b from #hhh group by a,b,id
--select id,a,b from #hhh group by a,b,id
--select distinct a from #hhh
select id,a,max(isnull(b,'')) from #hhh group by id,a
drop table #hhh继续,我想不出了
那就直接group by a ,id用子查询选出来。
select IDENTITY(int, 1,1) AS ID_Num,* into newtable from tableselect id,a,b from newtable
where ID_Num in (select min(ID_Num) from newtable group by a)
(id int,
a varchar(100),
b varchar(100)
)
insert into #hhh values ('1','a1','E')
insert into #hhh values ('2','a1','')
insert into #hhh values ('3','a2','E')
insert into #hhh values ('4','a3','')
--select top 1 id,a,b from #hhh group by a,b,id
--select id,a,b from #hhh group by a,b,id
--select distinct a from #hhh
select distinct A,Id,B from #hhh
--select id,a,max(isnull(b,'')) from #hhh group by id,a
drop table #hhh--结果:
a1 1 E
a1 2
a2 3 E
a3 4