如何在使用多个连接的情况下保留密钥？

Question

在下面的代码中，我创建了一个视图 table，用于显示员工相关数据。对于每个员工，我需要从员工那里获取所有专栏，以及从 "department" table 获取 "dept_title" 和从 "unit" table 获取 "unit_title"。基本上我已经 LEFT JOINED "staff" table 与 INNER JOINING "unit" table 和 "unit_staff" staff table("unit_staff" 的结果是单元和员工之间的连接 table）。连接这三个 table 的结果与 "department" table 左连接。所以现在我在同一视图中拥有来自三个不同 table 的所有不同列。

( staff-----left join-----> ( unit-----内连接----->unit_staff ) ) -----左加入----->部门

CREATE OR REPLACE FORCE VIEW "V_STAFF" (
    "STAFF_ID", 
    "STAFF_NAME",
    "SALUTATION",
    "GENDER", 
    "CONTACT_NO", 
    "PRIMARY_EMAIL", 
    "SECONDARY_EMAIL", 
    "DOB", "ADDRESS", 
    "NATIONALITY", 
    "STAFF_TYPE", 
    "DEPT_NAME",
    "UNITS_NAME"
) AS 
SELECT staff.staff_id, 
staff.staff_name,
staff.salutation,
staff.gender,
staff.contact_no,
staff.primary_email,
staff.secondary_email,
staff.dob,
staff.address,
staff.nationality,
staff.staff_type,
department.dept_title,
LISTAGG(unit_title, ',') WITHIN GROUP (ORDER BY unit_title) AS units
FROM (staff
LEFT JOIN (unit_staff INNER JOIN unit ON unit_staff.unit_id = unit.unit_id)
ON staff.staff_id = unit_staff.staff_id) LEFT JOIN department ON staff.dept_id = department.dept_id
GROUP BY staff.staff_id, 
staff.staff_name,
staff.salutation,
staff.gender,
staff.contact_no,
staff.primary_email,
staff.secondary_email,
staff.dob,
staff.address,
staff.nationality,
staff.staff_type,
department.dept_title;
/

问题是键没有保留在视图中。之前，我没有在视图中包含 "department" table 并且在插入数据时我在密钥保存方面没有问题。所以我认为添加具有一对一关系的 "department" table 不会破坏密钥保存，但确实如此。我认为问题在于我对不同列进行分组的方式。我如何更改以上代码以保留密钥？

Answer 1

我认为删除聚合并使用子查询可以解决问题：

select s.*,
       (select listagg(u.unit_title, ',') WITHIN GROUP (ORDER BY unit_title) AS units
        from unit_staff us join
             unit u 
             on us.unit_id = u.unit_id
        where s.staff_id = us.staff_id)
       ) as units,
       (select d.dept_title
        from department d
        where s.dept_id = d.dept_id
       ) as dept_tital
from staff s;

如何在使用多个连接的情况下保留密钥？

How to preserve key where multiple joins are used?

sql

oracle

oracle-apex