【sql】七种join语句

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           今天看mysql视频，里边老师给总结了一下七种join语句，感觉挺好的。分享一下

select * from TableA a inner join TableB b on a.id =b.aid

 

 

select * from TableA a left join TableB b on a.id =b.aid

select * from TableA a right join TableB b on a.id =b.aid

select * from TableA a left join TableB b where b.aid is null

selet * from TableA a right join TableB b on a.id =b.aid where a.id is null

select * from TableA a left join TableB b on a.id =b.aid
union
select * from TableA a right join TableB b on a.id =b.aid

select * from TableA a left join TableB b where b.aid is null
union
select * from TableA a right join TableB b where a.id is null