提取不重复的数据,要怎么写如:表 aaaa bb cc dd
a s s d
a d d d
a e r r
b d f g
b g f f就是有aa字段中有重复的,就值显示一个 效果:
aa bb cc dd
a s s d
b d f g这样SQL语句要怎么写??
不要用到中间表的,就是不想用中间表看看有没有办法尽量最简单的语句,
知道的人教教我,XX
a s s d
a d d d
a e r r
b d f g
b g f f就是有aa字段中有重复的,就值显示一个 效果:
aa bb cc dd
a s s d
b d f g这样SQL语句要怎么写??
不要用到中间表的,就是不想用中间表看看有没有办法尽量最简单的语句,
知道的人教教我,XX
id name
11 aaaa
11 bbbb
11 cccc
22 dddd
22 eeee
22 ffff
如何将表中的相同id号的第一条记录取出来?即:
id name
11 aaaa
22 dddd
CREATE TABLE #a (
[id] [char] (10),
[name] [char] (10)
)insert into #a(id,name) values('11','aaaa')
insert into #a(id,name) values('11','bbbb')
insert into #a(id,name) values('11','cccc')
insert into #a(id,name) values('22','dddd')
insert into #a(id,name) values('22','eeee')
insert into #a(id,name) values('22','ffff') select * from #a b
where name=(select top 1 name from #a where id=b.id)drop table #aid name
---------- ----------
11 aaaa
22 dddd (所影响的行数为 2 行)
CREATE TABLE #a (
[id] [char] (10),
[name] [char] (10)
)insert into #a(id,name) values('11','aaaa')
insert into #a(id,name) values('11','bbbb')
insert into #a(id,name) values('11','cccc')
insert into #a(id,name) values('22','dddd')
insert into #a(id,name) values('22','eeee')
insert into #a(id,name) values('22','ffff') select id1=identity(int,1,1),* into #t from #a
go
select id,name from #t where id1 in(select min(id1) from #t group by id)drop table #a
drop table #tid name
---------- ----------
11 aaaa
22 dddd (所影响的行数为 2 行)