SQL：先按rowID排序，再根据rowid按列排序

Question

我有以下 'departments' table:

+-------+-------------+-------------------+
| rowid | department  | parent_department |
+-------+-------------+-------------------+
| 10    | Main Office | NULL              |
+-------+-------------+-------------------+
| 11    | Back Office | 10                |
+-------+-------------+-------------------+
| 12    | Commercial  | NULL              |
+-------+-------------+-------------------+
| 13    | Outdoor     | NULL              |
+-------+-------------+-------------------+
| 14    | Beach       | 13                |
+-------+-------------+-------------------+
| 15    | Gardening   | 13                |
+-------+-------------+-------------------+
| 16    | Accounting  | 10                |
+-------+-------------+-------------------+

我想根据 rowid 和 parent_department 订购它：

+-------+-------------+-------------------+
| rowid | department  | parent_department |
+-------+-------------+-------------------+
| 10    | Main Office | NULL              |
+-------+-------------+-------------------+
| 11    | Back Office | 10                |
+-------+-------------+-------------------+
| 16    | Accounting  | 10                |
+-------+-------------+-------------------+
| 13    | Outdoor     | NULL              |
+-------+-------------+-------------------+
| 14    | Beach       | 13                |
+-------+-------------+-------------------+
| 15    | Gardening   | 13                |
+-------+-------------+-------------------+
| 12    | Commercial  | NULL              |
+-------+-------------+-------------------+

因此，对于每个 rowid，查找 'parents_departments' 是否存在，并显示如下顺序。

请注意，我没有设计当前的 table 遗憾的是我没有更改它的权限

Answer 1

试试这个：

SELECT rowid, department, parent_department
  FROM departments
 ORDER BY IFNULL(parent_department, rowid), rowid;

SQL：先按rowID排序，再根据rowid按列排序

SQL: Order by rowID and then by column based on the rowid

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