inner join ,left join ,right join 的区别

 注意下图当：left join tbl_EmployeeLD c on a.EmpNum = c.EmpNum

注意下图当：left join tbl_EmployeeLD c on b.EmpNum = c.EmpNum

 

 

posted @ 2009-04-06 22:32  杨子宜  阅读(182)  评论(0)  编辑  收藏  举报