查找表中某两列值重复的行
例子
select * from relation_map a
where exists (
select 1
from relation_map b
where b.primary_id = a.primary_id
and (a.slave_id<> b.slave_id)
)
例子
select * from relation_map a
where exists (
select 1
from relation_map b
where b.primary_id = a.primary_id
and (a.slave_id<> b.slave_id)
)