create table liuzixi ( a varchar(10), b varchar(10) )insert into liuzixi select 'A','B' union all select 'A','C' union all select 'A','B' select distinct * from liuzixi
select * from [Table] a where not exists(select 1 from [Table] where b=a.b and a<>a.a)
create table liuzixi
(
a varchar(10),
b varchar(10)
)insert into liuzixi
select 'A','B' union all
select 'A','C' union all
select 'A','B' select distinct * from liuzixi
select B,min(A) from liuzixi group by B