select realname as hname from a, b where b.h_id=a.id
select realname as pname from a,b where b.p_id=a.id
我想把 pname和hname 同时显示,还需要怎么做啊
select realname as pname from a,b where b.p_id=a.id
我想把 pname和hname 同时显示,还需要怎么做啊
select (select realname from b where h_id = a.id) as hname,
(select realname from b where p_id = a.id) as pname
from a--或:select t.realname as hname,e.realname as pname
from a left join b t on a.id = t.h_id
left join b e on a.id = e.p_id--都不行?
select realname as pname from a,b where b.p_id=a.id想要什么结果?通过A.ID连接?试试下面的看看哪种是你想要的
select a.hname,b.pname
from
(select realname as hname,a.id as id from a, b where b.h_id=a.id) a,
(select realname as pname ,a.id as id from a,b where b.p_id=a.id) b
where a.id=b.id
(select realname from b where b.h_id=a.id) hname ,
(select realname from b where b.p_id=a.id) pname
from a---应该还有其他的关联字段 有的话可以case 来做
select realname as pname from a,b where b.p_id=a.id查询出的结果数量是不一样的
select '' as hname,realname as pname from a,b where b.p_id=a.id;
select a.hname,b.pname
from
(select realname as hname,a.id as id from a, b where b.h_id=a.id) a,
(select realname as pname ,a.id as id from a,b where b.p_id=a.id) b
where a.id(+)=b.id(+)
union all
select 'p_id' id_type, realname as pname from a,b where b.p_id=a.id