今天在csdn上看到一篇报道,关于如何甄别面试者的一些技巧,发现了几个知识点,总结了一下
(1)select *from talbeA as a left join tableB as b on a.key=b.key (2)select *from talbeA as a left join tableB as b on a.key=b.key where b.key is null (3) select *from talbeA as a inner join tableB as b on a.key=b.key (4)select *from talbeA as a right join tableB as b on a.key=b.key (5)select *from talbeA as a right join tableB as b on a.key=b.key where a.key is null (6)select *from talbeA as a outer join tableB as b on a.key=b.key (7)select *from talbeA as a outer join tableB as b on a.key=b.key where a.key is null and b.key is null