请问一下这个语句如何写？

[Lansie]

id class type
1 1 A
2 1 B
3 2 A
4 1 D
5 2 C

现在需要把type中既有'A'又有'B'的class选出来

类似的语句怎么写？

谢谢了

[-狙击手-]

select a.class
from ta a
left join (select * from ta where type = 'B') b on a.class = b.class
where a.type = 'A'

[wzy_love_sly]

declare @tb table(id int,class int,type varchar(50))
insert into @tb select 1,1,'a'
insert into @tb select 2,1,'b'
insert into @tb select 3,2,'a'
insert into @tb select 4,1,'d'
insert into @tb select 5,2,'c'

select * from @tb t where exists(
select 1 from @tb where class=t.class and type in('a','b')
group by class
having count(distinct type)=2
)

id class type
1 1 a
2 1 b
4 1 d

[-狙击手-]

declare @tb table(id int,class int,type varchar(50))
insert into @tb select 1,1,'a'
insert into @tb select 2,1,'b'
insert into @tb select 3,2,'a'
insert into @tb select 4,1,'d'
insert into @tb select 5,2,'c'
select a.class 
from @tb a 
inner join (select * from @tb where type = 'B') b on a.class = b.class 
where a.type = 'A'

/*
class       
----------- 
1

（所影响的行数为 1 行）
*/

[Julyseven]

select class
from   表
group  by class
having count(distinct type) >= 2

[律己修心]

[Quote=引用 3 楼 happyflystone 的回复:]
SQL codedeclare @tb table(id int,class int,type varchar(50))
insert into @tb select 1,1,'a'
insert into @tb select 2,1,'b'
insert into @tb select 3,2,'a'
insert into @tb select 4,1,'d'
insert into @tb select 5,2,'c'
select a.class
from @tb a
inner join (select * from @tb where type = 'B') b on a.class = b.class
where a.type = 'A'

/*
class
-----------
1

（所影响的行数…
[/Quote]

[yinle2008]

-- -- select * from student
-- -- create table data(
-- -- idc char(2),
-- -- class char(2),
-- -- type char(1))
-- -- select * from data
-- -- insert into data
-- -- values ('5','2','c');
-- -- select * from data
-- select * from data
-- where type ='a'or type ='b';

[hanjs]

declare @tb table(id int,class int,type varchar(50))
insert into @tb select 1,1,'a'
insert into @tb select 2,1,'b'
insert into @tb select 3,2,'a'
insert into @tb select 4,1,'d'
insert into @tb select 5,2,'c'
select a.class 
from @tb a inner join @tb b 
on a.class = b.class and b.type='b' and a.type = 'A'

[rcshadow]

我的方法简单
declare @tb table(id int,class int,type varchar(50))
insert into @tb select 1,1,'a'
insert into @tb select 2,1,'b'
insert into @tb select 3,2,'a'
insert into @tb select 4,1,'d'
insert into @tb select 5,2,'c'

select class ,type from @tb
where type='a' or type='b'

如果多就用type in ('a','b','c','d')

[灰太狼]

create table #t1(id int,class int, [type] nvarchar(10))

insert into #t1
	select 1,  1    ,'A' union all
	select 2,  1   , 'B' union all
	select 3 , 2  ,  'A' union  all
	select 4  ,1 ,   'D' union  all
	select 5  ,2,    'C' 

select * from #t1

select a.class from #t1 as a
join #t1 as b on a.class = b.class
where a.[type] = 'A' and b.[type] = 'B'

[rhq1234]

select class
from 表
where type in('a','b')
group by class
having count(distinct type) >= 2

[tyrone_wang]

select class
from 表
where type='A'
intersect
select class
from 表
where type='B'

或者
select class
from 表
where type='A' and class in
(
select class
from 表
where type='B'
);

[win7cc]

select ....from...where ...or...

[changweishao]

select class,* from tbName where type in('A','B')

[-晴天]

declare @tb table(id int,class int,type varchar(50))
insert into @tb select 1,1,'A'
insert into @tb select 2,1,'B'
insert into @tb select 3,2,'A'
insert into @tb select 4,1,'D'
insert into @tb select 5,2,'C'

select distinct class from @tb a where exists (select 1 from @tb where class=a.class and type='A') and type='B'

/*
class
-----------
1

(1 行受影响)
*/

[-晴天]

declare @tb table(id int,class int,type varchar(50))
insert into @tb select 1,1,'A'
insert into @tb select 2,1,'B'
insert into @tb select 3,2,'A'
insert into @tb select 4,1,'D'
insert into @tb select 5,2,'C'
insert into @tb select 6,1,'C'

select class from @tb where type in('A','B','C','D') group by class having count(distinct type)=4

/*
class
-----------
1

(1 行受影响)
*/

[cxmcxm]

select distinct class from 表 as a 
where exists(select * from 表 where class=a.class and type='A')
	and exists(select * from 表 where class=a.class and type='B')

[Lansie]

谢谢大家的回答
我是想看一下有什么好的办法可以解决这一类问题

上面有不少兄弟的答复都可以解决

但如果再增加几个条件呢，比如要有'A'，'B','C','D','E'的class选出来
这样答复中的解法就有点繁琐了