mysql左连接与oracle(+)使用对比 由于mysql不能像oracle一样使用(+)做外连接，使用left join或者right join需要注意 oracle： select a.aid aid , b.bid bid ,c.cid cid , d.did did , e.eid eid from tablea a , tableb b ,tablec c ,tabled d ,tablee e whe
mysql左连接与oracle(+)使用对比oracle： select a.aid aid , b.bid bid ,c.cid cid , d.did did , e.eid eid from tablea a , tableb b , tablec c , tabled d , tablee e where a.aid = b.aid (+) and a.aid = c.aid(+) and b.bid = d.bid (+) and d.did = e.eid (+) order by a.aid , b.bid , c.cid , d.did ,e.eid ; mysql： select a.aid aid , b.bid bid ,c.cid cid , d.did did , e.eid eid from tablea a left join ( tableb b left join ( tabled d left join tablee e on (d.did = e.eid) ) on (b.bid = d.bid ) ) on ( a.aid = b.aid) left join tablec c on a.aid = c.aid order by a.aid , b.bid , c.cid , d.did ,e.eid ;
