请教个查询重复数据的问题
查询并显示出所有重复的数据 
 字段: 
 id            A            B 
 1               a            b 
 2               a            c 
 3               a            b     
 查询结果 
 id            A            B 
 1               a            b 
 3               a            b
------解决方案--------------------select * from [Table] a where exists(select count(1) from [Table] where a=a.a and b=a.b group by a,b)> 1
------解决方案--------------------create table #t(id int,A char(1),B char(1)) 
 insert into #t 
 select 1, 'a ', 'b ' 
 union all select 2, 'a ', 'c ' 
 union all select 3, 'a ', 'b '   
 select * from #t a 
 where exists(select 1 from #t b where a.A=b.A and a.B=b.B and a.id <> b.id)   
 drop table #t   
 /* 
 id          A    B     
 ----------- ---- ----  
 1           a    b 
 3           a    b   
 (所影响的行数为 2 行) 
 */
------解决方案--------------------select * from 表名 t where (select count(1) from 表名 where t.a=a and t.b=b) > 1
------解决方案------------------------ 用ls的数据 ---- 
 create table #t(id int,A char(1),B char(1)) 
 insert into #t 
 select 1, 'a ', 'b ' 
 union all select 2, 'a ', 'c ' 
 union all select 3, 'a ', 'b '   
 select * from #t t where (select count(1) from #t where t.a=a and t.b=b) > 1