SQLServer多表连接查询

双表内部连接查询

select wName,dName from  DepartMent,Worker where DepartMent.dID=Worker.did

select wName,dName from  DepartMent inner join Worker on DepartMent.dID=Worker.did

多表内部连接查询

select wName,dName,GName from  DepartMent,Worker,Gender

where DepartMent.dID=Worker.did and Worker.Gid = Gender.Gid

select wName,dName,GName from  DepartMent

inner join Worker on DepartMent.dID=Worker.did

inner join Gender on Worker.Gid=Gender.Gid

外部连接查询

--1.左外连接查询

select wName,dName from  DepartMent

left outer join Worker on DepartMent.dID=Worker.did

--2.右外连接查询

select wName,dName from  DepartMent

right outer join Worker on DepartMent.dID=Worker.did

--3.完全外部连接查询

select wName,dName from  DepartMent

full outer join Worker on DepartMent.dID=Worker.did

--4.交叉连接

select wName,dName from  DepartMent

Cross join Worker

select wName,dName from  DepartMent, Worker