Join 语句详解

功能概述

JOIN 语句是 SQL 中用于连接多个表的核心操作，它基于表之间的关联关系将数据组合在一起，形成更完整的数据视图。

Inner Join

select * from sx1 join sx2 on sx1.sid = sx2.

Full Join

select * from sx1 full join sx2 on sx1.sid = sx2.sid

Left Join

select * from sx1 left join sx2 on sx1.sid = sx2.sid

Left Semi Join

select * from sx1 left semi join sx2 on sx1.sid = sx2.sid

Left Anti-Semi Join

select * from sx1 left anti join sx2 on sx1.sid = sx2.sid

Right Join

select * from sx1 right join sx2 on sx1.sid = sx2.sid

Right Semi Join

select * from sx1 right semi join sx2 on sx1.sid = sx2.sid

Right Anti-Semi Join

select * from sx1 right anti join sx2 on sx1.sid = sx2.sid

Natural Join

select * from sx1 natural join sx2

Cross Join

select * from sx1 cross join sx2