# Sales Person Problem

## Description

LeetCode Problem 607.

Given three tables: salesperson, company, orders. Output all the names in the table salesperson, who didn’t have sales to company ‘RED’.

Example Input

Table: salesperson

``````1
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+----------+------+--------+-----------------+-----------+
| sales_id | name | salary | commission_rate | hire_date |
+----------+------+--------+-----------------+-----------+
|   1      | John | 100000 |     6           | 4/1/2006  |
|   2      | Amy  | 120000 |     5           | 5/1/2010  |
|   3      | Mark | 65000  |     12          | 12/25/2008|
|   4      | Pam  | 25000  |     25          | 1/1/2005  |
|   5      | Alex | 50000  |     10          | 2/3/2007  |
+----------+------+--------+-----------------+-----------+
The table salesperson holds the salesperson information. Every salesperson has a sales_id and a name.
``````

Table: company

``````1
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+---------+--------+------------+
| com_id  |  name  |    city    |
+---------+--------+------------+
|   1     |  RED   |   Boston   |
|   2     | ORANGE |   New York |
|   3     | YELLOW |   Boston   |
|   4     | GREEN  |   Austin   |
+---------+--------+------------+
The table company holds the company information. Every company has a com_id and a name.
``````

Table: orders

``````1
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+----------+------------+---------+----------+--------+
| order_id | order_date | com_id  | sales_id | amount |
+----------+------------+---------+----------+--------+
| 1        |   1/1/2014 |    3    |    4     | 100000 |
| 2        |   2/1/2014 |    4    |    5     | 5000   |
| 3        |   3/1/2014 |    1    |    1     | 50000  |
| 4        |   4/1/2014 |    1    |    4     | 25000  |
+----------+----------+---------+----------+--------+
The table orders holds the sales record information, salesperson and customer company are represented by sales_id and com_id.
``````

Output

``````1
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+------+
| name |
+------+
| Amy  |
| Mark |
| Alex |
+------+
``````

Explanation

According to order ‘3’ and ‘4’ in table orders, it is easy to tell only salesperson ‘John’ and ‘Pam’ have sales to company ‘RED’, so we need to output all the other names in the table salesperson

## MySQL Solution

``````1
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select s.name
from salesperson s
where s.sales_id not in
(select o.sales_id
from orders o
left join company c on o.com_id = c.com_id
where c.name = 'RED')
``````