mysql> select * from sales;
+----+--------------+-------------+
| id | product_name | sale_amount |
+----+--------------+-------------+
| 1 | Product A | 100.50 |
| 2 | Product B | 75.25 |
| 3 | Product A | 120.75 |
| 4 | Product C | 50.00 |
| 5 | Product B | 90.80 |
| 6 | Product R | 300.00 |
+----+--------------+-------------+
6 rows in set (0.00 sec)
mysql> select * from clients;
+-----------+-------------+-------------------+
| client_id | client_name | registration_date |
+-----------+-------------+-------------------+
| 1 | Alice | 2023-01-10 |
| 2 | Bob | 2023-02-15 |
| 3 | Charlie | 2023-03-20 |
| 4 | Ambiorix | 2024-10-06 |
| 5 | Many | 2024-10-11 |
+-----------+-------------+-------------------+
5 rows in set (0.00 sec)
mysql> select c.client_name,c.client_id,s.id,s.product_name from clients as c INNER JOIN sales as s on s.id=c.client_id;
+-------------+-----------+----+--------------+
| client_name | client_id | id | product_name |
+-------------+-----------+----+--------------+
| Alice | 1 | 1 | Product A |
| Bob | 2 | 2 | Product B |
| Charlie | 3 | 3 | Product A |
| Ambiorix | 4 | 4 | Product C |
| Many | 5 | 5 | Product B |
+-------------+-----------+----+--------------+
5 rows in set (0.00 sec)
mysql> select c.client_name,c.client_id,s.id,s.product_name from clients as c LEFT JOIN sales as s on s.id=c.client_id;
+-------------+-----------+------+--------------+
| client_name | client_id | id | product_name |
+-------------+-----------+------+--------------+
| Alice | 1 | 1 | Product A |
| Bob | 2 | 2 | Product B |
| Charlie | 3 | 3 | Product A |
| Ambiorix | 4 | 4 | Product C |
| Many | 5 | 5 | Product B |
+-------------+-----------+------+--------------+
5 rows in set (0.00 sec)
mysql> select c.client_name,c.client_id,s.id,s.product_name from clients as c RIGHT JOIN sales as s on s.id=c.client_id;
+-------------+-----------+----+--------------+
| client_name | client_id | id | product_name |
+-------------+-----------+----+--------------+
| Alice | 1 | 1 | Product A |
| Bob | 2 | 2 | Product B |
| Charlie | 3 | 3 | Product A |
| Ambiorix | 4 | 4 | Product C |
| Many | 5 | 5 | Product B |
| NULL | NULL | 6 | Product R |
+-------------+-----------+----+--------------+