﻿ SQL: Salesman will appear for all customer and vice versa

# SQL Exercise: Salesman will appear for all customer and vice versa

## SQL JOINS: Exercise-17 with Solution

Write a SQL query to combine each row of the salesman table with each row of the customer table.

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:

``````-- Selecting all columns from the Cartesian product of the 'salesman' and 'customer' tables
SELECT *
-- Specifying the tables to perform the cross join ('salesman' as 'a' and 'customer' as 'b')
FROM salesman a
CROSS JOIN customer b;
``````

Output of the Query:

```salesman_id	name	city		commission	customer_id	cust_name	city		grade	salesman_id
5001	James Hoog	New York	0.15		3002		Nick Rimando	New York	100	5001
5002	Nail Knite	Paris		0.13		3002		Nick Rimando	New York	100	5001
5005	Pit Alex	London		0.11		3002		Nick Rimando	New York	100	5001
5006	Mc Lyon		Paris		0.14		3002		Nick Rimando	New York	100	5001
5007	Paul Adam	Rome		0.13		3002		Nick Rimando	New York	100	5001
5003	Lauson Hen	San Jose	0.12		3002		Nick Rimando	New York	100	5001
5001	James Hoog	New York	0.15		3007		Brad Davis	New York	200	5001
5002	Nail Knite	Paris		0.13		3007		Brad Davis	New York	200	5001
5005	Pit Alex	London		0.11		3007		Brad Davis	New York	200	5001
5006	Mc Lyon		Paris		0.14		3007		Brad Davis	New York	200	5001
5007	Paul Adam	Rome		0.13		3007		Brad Davis	New York	200	5001
5003	Lauson Hen	San Jose	0.12		3007		Brad Davis	New York	200	5001
5001	James Hoog	New York	0.15		3005		Graham Zusi	California	200	5002
5002	Nail Knite	Paris		0.13		3005		Graham Zusi	California	200	5002
5005	Pit Alex	London		0.11		3005		Graham Zusi	California	200	5002
5006	Mc Lyon		Paris		0.14		3005		Graham Zusi	California	200	5002
5007	Paul Adam	Rome		0.13		3005		Graham Zusi	California	200	5002
5003	Lauson Hen	San Jose	0.12		3005		Graham Zusi	California	200	5002
5001	James Hoog	New York	0.15		3008		Julian Green	London		300	5002
5002	Nail Knite	Paris		0.13		3008		Julian Green	London		300	5002
5005	Pit Alex	London		0.11		3008		Julian Green	London		300	5002
5006	Mc Lyon		Paris		0.14		3008		Julian Green	London		300	5002
5007	Paul Adam	Rome		0.13		3008		Julian Green	London		300	5002
5003	Lauson Hen	San Jose	0.12		3008		Julian Green	London		300	5002
5001	James Hoog	New York	0.15		3004		Fabian Johnson	Paris		300	5006
5002	Nail Knite	Paris		0.13		3004		Fabian Johnson	Paris		300	5006
5005	Pit Alex	London		0.11		3004		Fabian Johnson	Paris		300	5006
5006	Mc Lyon		Paris		0.14		3004		Fabian Johnson	Paris		300	5006
5007	Paul Adam	Rome		0.13		3004		Fabian Johnson	Paris		300	5006
5003	Lauson Hen	San Jose	0.12		3004		Fabian Johnson	Paris		300	5006
5001	James Hoog	New York	0.15		3009		Geoff Cameron	Berlin		100	5003
5002	Nail Knite	Paris		0.13		3009		Geoff Cameron	Berlin		100	5003
5005	Pit Alex	London		0.11		3009		Geoff Cameron	Berlin		100	5003
5006	Mc Lyon		Paris		0.14		3009		Geoff Cameron	Berlin		100	5003
5007	Paul Adam	Rome		0.13		3009		Geoff Cameron	Berlin		100	5003
5003	Lauson Hen	San Jose	0.12		3009		Geoff Cameron	Berlin		100	5003
5001	James Hoog	New York	0.15		3003		Jozy Altidor	Moscow		200	5007
5002	Nail Knite	Paris		0.13		3003		Jozy Altidor	Moscow		200	5007
5005	Pit Alex	London		0.11		3003		Jozy Altidor	Moscow		200	5007
5006	Mc Lyon		Paris		0.14		3003		Jozy Altidor	Moscow		200	5007
5007	Paul Adam	Rome		0.13		3003		Jozy Altidor	Moscow		200	5007
5003	Lauson Hen	San Jose	0.12		3003		Jozy Altidor	Moscow		200	5007
5001	James Hoog	New York	0.15		3001		Brad Guzan	London			5005
5002	Nail Knite	Paris		0.13		3001		Brad Guzan	London			5005
5005	Pit Alex	London		0.11		3001		Brad Guzan	London			5005
5006	Mc Lyon		Paris		0.14		3001		Brad Guzan	London			5005
5007	Paul Adam	Rome		0.13		3001		Brad Guzan	London			5005
5003	Lauson Hen	San Jose	0.12		3001		Brad Guzan	London			5005
```

Explanation:

The said SQL query is performing a CROSS JOIN (also known as a Cartesian product) between the salesman table aliased as a and the customer table aliased as b.
The result of this query will be a new table that contains every possible combination of rows from the salesman table and the customer table. The "SELECT *" statement is selecting all columns from the resulting table.

Visual Explanation:

## Query Visualization:

Duration:

Rows:

Cost:

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Previous SQL Exercise: Customer who is neither in the list nor have a grade.
Next SQL Exercise: All customers will be served by a salesman from a city.

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