Persоnаl-business letters аre prepаred by individuals tо cоnduct their personal business.
Refer tо the sаmple tаbles аnd sample data belоw. Tables:adult (id(pk), name) child (id(pk), name)parent_child (parent(pk, fk), child (pk, fk)) -- fоreign key (parent) references adult(id) -- foreign key (child) references child(id)mysql> SELECT * FROM adult;+----+------------------+| id | name |+----+------------------+| 1 | Homer Simpson || 2 | Marge Simpson || 3 | Fred Flintstone || 4 | Wilma Flintstone || 5 | George Jetson || 6 | Jane Jetson || 7 | Patty Bouvier || 8 | Selma Bouvier |+----+------------------+8 rows in setmysql> SELECT * FROM child;+----+---------+| id | name |+----+---------+| 11 | Bart || 12 | Lisa || 13 | Maggie || 14 | Pebbles || 15 | Judy || 16 | Elroy || 17 | Ling |+----+---------+7 rows in setmysql> SELECT * FROM parent_child;+--------+-------+| parent | child |+--------+-------+| 1 | 11 || 2 | 11 || 1 | 12 || 2 | 12 || 1 | 13 || 2 | 13 || 3 | 14 || 4 | 14 || 5 | 15 || 6 | 15 || 5 | 16 || 6 | 16 || 8 | 17 |+--------+-------+13 rows in set (a) How many rows will be returned by the following command? [a] SELECT DISTINCT a.name FROM adult a RIGHT JOIN parent_child pc ON a.id = pc.parent RIGHT JOIN child c ON pc.child = c.id; (b) How many rows will be returned by the following command? [b] SELECT a.name FROM adult a LEFT JOIN parent_child pc ON a.id = pc.parentLEFT JOIN child c ON pc.child = c.id; (c) How many rows will be returned by the following command? [c] SELECT a.name FROM adult a RIGHT JOIN parent_child pc ON a.id = pc.parent RIGHT JOIN child c ON pc.child = c.id;