By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.
Records: 6 Duplicates: 0 Warnings: 0
| id_element | id_element_elements |
|---|---|
| elem1 | null |
| elem2 | elem1 |
| elem3 | elem1 |
| elem4 | elem2 |
| elem5 | null |
| elem6 | elem5 |
| id_element | id_child |
|---|---|
| elem1 | elem2 |
| elem1 | elem3 |
| elem2 | elem4 |