Question

我有2个表，我想做一个查询并根据它们的外键对它们进行分组。这是一个例子：

部门

DEPART_ID(PK) - DEPART_NAME

   1          - Accounting
   2          -    IT

员工

EMP_ID(PK) - NAME - SURNAME - DEPART_ID(FK)

  1        - John   - John   -    1
  2        - George - George -    2

管理者

MANAG_ID(PK) - NAME    - SURNAME   - DEPART_ID(FK)
     1       - Nick    - Nick      -     1
     2       - Michael - Michael   -     2

我希望按照部门名称对此输出进行分组。

Accounting      |       IT 
----------------|-------------------
John John       |   George George
Nick Nick       |   Michael Michael

我已经尝试但我不能让它发挥作用。这是最好的方法吗？

Answer 1

您可以使用此功能获得所需内容：

select *  from
(select name || ' ' || Surname Accounting from employees where depart_id = 1),
(select name || ' ' || Surname  IT from employees where depart_id =2)
union
select * from
(select name || ' ' || Surname Accounting from managers where depart_id = 1),
(select name || ' ' || Surname  IT from managers where depart_id =2)

Answer 2

这是一个解决方案。子查询格式化名称并为部门内的员工生成连接密钥。主查询将WITH输出拆分为基于depart_id的子查询，这些查询在生成的密钥上连接;完全外部联接允许部门拥有不同数量的人。

with emps as
    ( select depart_id, 
             name || ' ' || Surname  ename ,
             row_number() over (partition by depart_id order by emp_id) rn
      from employees)
select acct.ename as accounting
       , it.ename as IT
       , sal.ename as sales
       , hr.ename as hr
from (select * from emps where department_id = 1) acct
     full outer join (select * from emps where department_id = 2) it
     on acct.rn = it.rn 
     full outer join (select * from emps where department_id = 3)  sal
     on acct.rn = sal.rn 
     full outer join (select * from emps where department_id = 4)  hr
     on acct.rn = hr.rn 
order by acct.rn, it.rn, sal.rn, hr.rn
/

Oracle SQL - 基于外键查询2个表

2 个答案: