数据库查询问题

Question

查询结果为
     yyy       yjs
      ccc      yas
               ybs

Answer 1

使用连接：
表2.id=表1.id(+)------------------------
|                      |
|   相逢何必曾相识     |
|                      |
------------------------

Answer 2

SELECT a.departmentname,b.name
 from 表1 a,表2 b
 where a.id(+)=b.departmentid

Answer 3

SELECT (select departmentname from 表1 where id=departmentid) departmentname,name from 表2