------------------------------------
| id | name               | parent |
------------------------------------
| 1  | cat1               | 0      |
| 2  | cat1,sub1          | 1      |
| 3  | cat1,sub1,sub-sub1 | 2      |
| 4  | cat1,sub2          | 1      |
| 5  | cat2               | 0      |
| 6  | cat3               | 0      |
| 7  | cat3,sub1          | 6      |
------------------------------------