﻿ SQL: Customers from New York or not with a given grade

# SQL Exercise: Customers from New York or not with a given grade

## SQL Boolean Operator Statement: Exercise-4 with Solution

From the following table, write a SQL query to find customers who are either from the city 'New York' or who do not have a grade greater than 100. Return customer_id, cust_name, city, grade, and salesman_id.

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 all columns from the 'customer' table.
SELECT *
-- Specifies the table from which to retrieve the data (in this case, 'customer').
FROM customer
-- Filters the rows to only include those where either the 'city' column has the value 'New York'
-- or the 'grade' column does not have a value greater than 100.
WHERE city = 'New York' OR NOT grade > 100;
``````

Output of the Query:

```customer_id	cust_name	city		grade   salesman_id
3002		Nick Rimando	New York	100	5001
3007		Brad Davis	New York	200	5001
3009		Geoff Cameron	Berlin		100	5003
```

Code Explanation:

The said SQL query that is selecting all columns (*) from the 'customer' table where the value of the "city" column is 'New York' OR NOT the value of the "grade" column is greater than 100.
The query will return all rows from the 'customer' table that meet either of these conditions. As a result, all the rows where city is 'New York' and where grade is less than or equal to 100 will be returned as well.

Relational Algebra Expression:

Relational Algebra Tree:

Explanation:

Visual presentation:

## Query Visualization:

Duration:

Rows:

Cost:

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Previous SQL Exercise: Information using OR operator with given conditions.
Next SQL Exercise: Neither New York residents nor with a grade above 100.

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