I have the following table:

```
+----+-----------+------+
| ID | Parent_ID | Name |
+----+-----------+------+
|  1 | null      | A    |
|  2 | null      | B    |
|  3 | null      | C    |
|  4 | 1         | D    |
|  5 | 4         | E    |
|  6 | 2         | F    |
+----+-----------+------+

```

And I need to get table like this:

```
+----+------+
| ID | Name |
+----+------+
|  1 | A    |
|  2 | B    |
|  3 | C    |
|  4 | AD   |
|  5 | ADE  |
|  6 | BF   |
+----+------+

```

I checked the ORACLE related questions here, but I did't find anything useful.