Q607SalesPerson.sql

/*
607. Sales Person

Description:
Write an SQL query to report the names of all the salespersons who did not have any orders related to the company with the name "RED".

Return the result table in any order.

The query result format is in the following example.

 

Example 1:

Input: 
SalesPerson table:
+----------+------+--------+-----------------+------------+
| sales_id | name | salary | commission_rate | hire_date  |
+----------+------+--------+-----------------+------------+
| 1        | John | 100000 | 6               | 4/1/2006   |
| 2        | Amy  | 12000  | 5               | 5/1/2010   |
| 3        | Mark | 65000  | 12              | 12/25/2008 |
| 4        | Pam  | 25000  | 25              | 1/1/2005   |
| 5        | Alex | 5000   | 10              | 2/3/2007   |
+----------+------+--------+-----------------+------------+
Company table:
+--------+--------+----------+
| com_id | name   | city     |
+--------+--------+----------+
| 1      | RED    | Boston   |
| 2      | ORANGE | New York |
| 3      | YELLOW | Boston   |
| 4      | GREEN  | Austin   |
+--------+--------+----------+
Orders table:
+----------+------------+--------+----------+--------+
| order_id | order_date | com_id | sales_id | amount |
+----------+------------+--------+----------+--------+
| 1        | 1/1/2014   | 3      | 4        | 10000  |
| 2        | 2/1/2014   | 4      | 5        | 5000   |
| 3        | 3/1/2014   | 1      | 1        | 50000  |
| 4        | 4/1/2014   | 1      | 4        | 25000  |
+----------+------------+--------+----------+--------+
Output: 
+------+
| name |
+------+
| Amy  |
| Mark |
| Alex |
+------+
Explanation: 
According to orders 3 and 4 in the Orders table, it is easy to tell that only salesperson John and Pam have sales to company RED, so we report all the other names in the table salesperson.
*/

/* Solution */
select s.name from SalesPerson s where s.sales_id not in
(select s.sales_id from SalesPerson s inner join Orders o on s.sales_id=o.sales_id inner join Company c on o.com_id=c.com_id where c.name = "RED");
/* use a nested select query to filter out those person related to company "RED" and select all other person excluding those associated with "RED" company */