SQL Exercises: Find salesmen who earned the maximum commission.

SQL SUBQUERY : Exercise-9 with Solution

9. From the following tables, write a SQL query to find those salespeople who earned the maximum commission. Return ord_no, purch_amt, ord_date, and salesman_id.

salesman_id  name        city        commission
-----------  ----------  ----------  ----------
5001         James Hoog  New York    0.15
5002         Nail Knite  Paris       0.13
5005         Pit Alex    London      0.11
5006         Mc Lyon     Paris       0.14
5003         Lauson Hen  San Jose    0.12
5007         Paul Adam   Rome        0.13

ord_no      purch_amt   ord_date    customer_id  salesman_id
----------  ----------  ----------  -----------  -----------
70001       150.5       2012-10-05  3005         5002
70009       270.65      2012-09-10  3001         5005
70002       65.26       2012-10-05  3002         5001
70004       110.5       2012-08-17  3009         5003
70007       948.5       2012-09-10  3005         5002
70005       2400.6      2012-07-27  3007         5001
70008       5760        2012-09-10  3002         5001
70010       1983.43     2012-10-10  3004         5006
70003       2480.4      2012-10-10  3009         5003
70012       250.45      2012-06-27  3008         5002
70011       75.29       2012-08-17  3003         5007
70013       3045.6      2012-04-25  3002         5001

Sample Solution:

-- Selecting specific columns from the 'orders' table
SELECT ord_no, purch_amt, ord_date, salesman_id 
-- Specifying the table to retrieve data from ('orders')
FROM orders 
-- Filtering the results based on the condition that 'salesman_id' is in the result of a subquery
WHERE salesman_id IN (
    -- Subquery: Selecting 'salesman_id' from the 'salesman' table where 'commission' is equal to the maximum 'commission' in the 'salesman' table
    SELECT salesman_id 
    FROM salesman
    WHERE commission = (
        -- Subquery: Selecting the maximum 'commission' from the 'salesman' table
        SELECT MAX(commission) 
        FROM salesman
    )
);

Output of the Query:

ord_no | purch_amt |  ord_date  | salesman_id 
--------+-----------+------------+-------------
  70002 |     65.26 | 2012-10-05 |        5001
  70005 |   2400.60 | 2012-07-27 |        5001
  70008 |   5760.00 | 2012-09-10 |        5001
  70013 |   3045.60 | 2012-04-25 |        5001
(4 rows)

Explanation:

The said SQL statement is selecting certain columns (ord_no, purch_amt, ord_date, salesman_id) from a table called 'orders', and only returning the rows where the "salesman_id" matches the "salesman_id" of a salesman with the highest commission in another table called 'salesman'.

Visual Explanation:

Practice Online

Sample Database: inventory

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