SQL：通過ROWID，然後通過基於ROWID列順序

Question

我有以下'departments'表：

+-------+-------------+-------------------+ 
| 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    | 
+-------+-------------+-------------------+ 

，我想它基於ROWID和parent_department因此下令：

+-------+-------------+-------------------+ 
| 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，對於每個rowid，查找是否存在'parents_departments'並按如下所示顯示順序。

請注意，我沒有設計當前表，可悲的是我沒有去改變它

Answer 1

試試這個權限：

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