How to restore lft and rgt fields in nested set table by root_id?

Question

MySQL

There is a table built according to the nested set model. The lft and rgt fields are damaged in it, but the root_id is preserved. How can I restore (recalculate) the values ​​of the lft and rgt fields using only SQL (MySQL) tools?

+----+---------+-------+-------+
| id | root_id |  lft  |  rgt  |
+----+---------+-------+-------+
|  1 |       1 |  NULL |  NULL |
+----+---------+-------+-------+
|  2 |       1 |  NULL |  NULL |
+----+---------+-------+-------+
|  3 |       2 |  NULL |  NULL |
+----+---------+-------+-------+
|  4 |       4 |  NULL |  NULL |
+----+---------+-------+-------+
|  5 |       4 |  NULL |  NULL |
+----+---------+-------+-------+

Answer 1

For the given table - in any way. Nodes 1 and 4 have themselves as parents.
In the general case, add the `level` column - the level of the node and, since everything needs to be done using SQL, write a stored procedure that sets the node level for each line and rebuilds the `lft` and `rgt` fields for each line in ascending order of `level` ( see article ).