3、es('c7','cname7');--InerJoin和Join和,(如select*froma,bwherea.id=b.id),这三个效果一样.select*from a, bwhere a.bid=b.bid;select*fromajoinbona.bid=b.bid;select*fromainnerjoinbona.bid=b.bid; --LeftJoin和LeftOuterJoin左连接、左外连接,效果一样。select*fromaleftjoinbona.bid=b.bid;select*fromal