数据库
首页 > 数据库> > SQL多表联系查询

SQL多表联系查询

作者:互联网

SQL多表联系查询

首先二张表连接查询:A表:EUser  B表:ESchool

一、外连接:左连接、右连接、全然外连接。

左连接:left join 或 left outer join

  select * from EUser left join ESchool  on EUser.SchoolId=ESchool.ScholId 

右连接:right join 或 right outer join

select * from EUser right join ESchool  on EUser.SchoolId=ESchool.ScholId 

全然外连接:  full join 或 full outer join

  select * from EUser full join ESchool  on EUser.SchoolId=ESchool.ScholId 

二、内连接: join 或 inner join

select * from EUser INNER JOIN ESchool  on EUser.SchoolId=ESchool.ScholId 

三张表连接查询:A表:EUser  B表:ESchool  C表:EXibu

方法一:

  select * from EUser INNER JOIN ESchool  on EUser.SchoolId=ESchool.ScholId 
  INNER JOIN EXibu on ESchool.ScholId=EXibu.SchoolId and EUser.DepartmentId=EXibu.DepartmentId

方法二:

  select * from EUser as sc left join ESchool as s on s.ScholId=sc.SchoolId
  left join EXibu as c on c.DepartmentId=sc.DepartmentId

了解内连接与外连接可以:https://www.cnblogs.com/mvpbest/p/13879121.html

标签:EUser,SchoolId,join,ScholId,ESchool,查询,SQL,多表,连接
来源: https://www.cnblogs.com/mvpbest/p/15057401.html