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      if(object_id('A') > 0)
  drop table A
go
create table A(code int,date datetime)
insert into A
select 1,'2009-10-1'
union all select 1,'2009-10-05'
union all select 1,'2009-10-04'
union all select 1,'2009-10-02'
union all select 2,'2009-10-01'
union all select 2,'2009-10-02'
union all select 2,'2009-10-03'
union all select 3,'2009-10-05'
union all select 3,'2009-10-06'


if(object_id('test') > 0 )
  drop table test
go

create table test (name varchar(100),value int)
insert into test
select 'xuhong',11
union all select 'xuhong',22
union all select 'chengguan',33
union all select 'chengguan',44
union all select 'daidai',114


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  select * from A a where exists (select 1 from A where code = a.code  having count(1) >= 3 )  --È«²¿½á¹û²é³öÀ´
  select * from test a where exists(select 1 from test where a.name = name having count(1) >=2) --²é³ö²¿ÃŽá¹û
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select * from test a where exists(select 1 from test where a.name = 'xuhong')
select * from A a where exists(sel