+----+------+---------+
| id | data | count_b |
+----+------+---------+
|  1 | blah |      2  |
|  2 | blah |      0  |
|  3 | blah |      1  |
+----+------+---------+

+----+------+--------+
| id | data | parent |
+----+------+--------+
|  1 | blah |      1 |
|  2 | blah |      1 |
|  3 | blah |      3 |
+----+------+--------+