SQL Exercises: Customer and salesmen who lives in the same city

Last update on March 08 2025 07:43:12 (UTC/GMT +8 hours)

Sales & City Matching

From the following tables, write a SQL query to find the salespeople and customers who live in the same city. Return customer name, salesperson name and salesperson city.

Sample table: salesman

 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
        5007 | Paul Adam  | Rome     |       0.13
        5003 | Lauson Hen | San Jose |       0.12

Sample table: customer

 customer_id |   cust_name    |    city    | grade | salesman_id 
-------------+----------------+------------+-------+-------------
        3002 | Nick Rimando   | New York   |   100 |        5001
        3007 | Brad Davis     | New York   |   200 |        5001
        3005 | Graham Zusi    | California |   200 |        5002
        3008 | Julian Green   | London     |   300 |        5002
        3004 | Fabian Johnson | Paris      |   300 |        5006
        3009 | Geoff Cameron  | Berlin     |   100 |        5003
        3003 | Jozy Altidor   | Moscow     |   200 |        5007
        3001 | Brad Guzan     | London     |       |        5005

Sample Solution:

-- This query selects specific columns ('customer.cust_name', 'salesman.name', 'salesman.city') from the 'salesman' and 'customer' tables.
-- It retrieves data where the 'city' column in the 'salesman' table matches the 'city' column in the 'customer' table.
SELECT customer.cust_name, salesman.name, salesman.city
-- Specifies the tables from which to retrieve the data (in this case, 'salesman' and 'customer').
FROM salesman, customer
-- Specifies the condition for joining the 'salesman' and 'customer' tables based on the equality of the 'city' columns.
WHERE salesman.city = customer.city;

Output of the query:

cust_name	name		city
Nick Rimando	James Hoog	New York
Brad Davis	James Hoog	New York
Julian Green	Pit Alex	London
Fabian Johnson	Mc Lyon		Paris
Fabian Johnson	Nail Knite	Paris
Brad Guzan	Pit Alex	London

Code Explanation:

The said query in SQL that joins the 'salesman' and 'customer' tables based on the city column. The result set includes the customer name (cust_name), salesman name (name), and city from the salesman table. The WHERE clause specifies the join condition between the two tables, which is that the city column must be equal in both tables.

Relational Algebra Expression:

Relational Algebra Tree:

Explanation:

Visual presentation:

Practice Online

Query Visualization:

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Cost:

For more Practice: Solve these Related Problems:

• Write a SQL query to list each salesperson along with the count of customers living in the same city.
• Write a SQL query to retrieve salespeople and customers sharing the same city, but only for cities with more than two customers.
• Write a SQL query to display the names of salespeople and customers who reside in the same city, ensuring each pair appears only once.
• Write a SQL query to find salespeople whose city has at least one customer, and include the city name in the output.
• Write a SQL query to list salespeople and corresponding customers from the same city, filtering out cities that start with the letter 'A'.

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