SQL group by

 

select a.* from 表 a where (select count(*) from 表 where 字段=a.字段)>1


select * from 表 where 字段 in(select 字段 from 表 group by 字段 having count(1)>1) 

--如果不能通过一个字段确定一行的话,可以把多个字段都转换成字符型串起来 

select * from 表 where convert(varchar(100),字段1)+convert(varchar(100),字段2) in(select convert(varchar(100),字段1)+convert(varchar(100),字段2) from 表 group by convert(varchar(100),字段1)+convert(varchar(100),字段2) having count(1)>1)




select 字段1,字段2,字段3,字段4...(所有字段) 
from t1 
group by 字段1,字段2,字段3,字段4...(所有字段) 
having count(*)>1




select * from 表 t 
where (select count(1) 
from 表 
where 字段1=t.字段1 
and 字段2=t.字段2 
and 字段3=t.字段3 
............. 
)>1 
 


select PermissionString 
from roleadmin 
where roleid in (1,3)
group by PermissionString 
having count(distinct roleid)=2