select b1.syname as jlname,b2.syname as subjlname from a,b b1,b b2 where a.jlno=b1.syno and a.subjlno=b2.syno
select jlname = (select b.sysname from b where b.syno = a.jlno), subjlname = (select b.sysname from b where b.syno = a.subjlno) from a select a.*, (select b.sysname from b where b.syno = a.jlno), (select b.sysname from b where b.syno = a.subjlno) from a
to rucypli : subjlno为空的情况下,你找不到该值的
to fcuandy:找的列就是jlno和subjlno对应的syname啊,用别名jlname,subjlname
select jlname=t2.syname,subjlname=t3.syname from a t1 left join b t2 on t1.jlno=t2.syno left join b t3 on t1.subjlno=t3.syno
from a,b b1,b b2
where a.jlno=b1.syno and a.subjlno=b2.syno
jlname = (select b.sysname from b where b.syno = a.jlno),
subjlname = (select b.sysname from b where b.syno = a.subjlno)
from a
select a.*,
(select b.sysname from b where b.syno = a.jlno),
(select b.sysname from b where b.syno = a.subjlno)
from a
subjlno为空的情况下,你找不到该值的
from a t1
left join b t2 on t1.jlno=t2.syno
left join b t3 on t1.subjlno=t3.syno