When and How to Use OR in SQL?

Welcome back to our SQL tutorial series! We’ve already covered how to use the AND operator to combine multiple conditions in your SQL queries. In this article, we’ll focus on the OR operator, which allows you to retrieve records that meet at least one of several conditions. Understanding how to use OR effectively can help you create more flexible and inclusive queries.

Understanding the OR Operator

The OR operator is used to combine multiple conditions in an SQL query. If any of the conditions separated by OR is true, the record will be included in the result set. This is useful when you want to filter data based on multiple criteria where any one of them can be sufficient.

Basic Syntax of OR

The basic syntax of the OR operator is as follows:

SELECT column1, column2, ...
FROM table_name
WHERE condition1 OR condition2 OR condition3 ...;

Let’s look at some practical examples to understand how to use the OR operator effectively.

Example Table: employees

We’ll continue to use the employees table for our examples:

Using OR to Combine Conditions

Example 1: Multiple Conditions in WHERE

To select employees who are either Software Engineers or Data Analysts, you use:

SELECT * FROM employees WHERE position = 'Software Engineer' OR position = 'Data Analyst';

This command returns:

Example 2: Combining Multiple Conditions

To select employees who have a salary less than $65,000 or are Project Managers, you use:

SELECT * FROM employees WHERE salary < 65000 OR position = 'Project Manager';

This command returns:

Here, either the salary condition or the position condition must be true for a record to be included in the result set.

Using OR with Other SQL Clauses

Example 3: OR with AND

You can combine OR with AND to create more complex conditions. For instance, to find employees who are either Software Engineers or Data Analysts and have a salary greater than $60,000:

SELECT * FROM employees WHERE (position = 'Software Engineer' OR position = 'Data Analyst') AND salary > 60000;

This command returns:

The parentheses ensure that the conditions inside them are evaluated together.

Example 4: OR with ORDER BY

To sort employees who are either Software Engineers or Data Analysts by their salaries in descending order:

SELECT * FROM employees WHERE position = 'Software Engineer' OR position = 'Data Analyst' ORDER BY salary DESC;

This command returns:

Example 5: OR with SELECT DISTINCT

To select distinct positions of employees who either have a salary greater than $70,000 or are Data Analysts:

SELECT DISTINCT position FROM employees WHERE salary > 70000 OR position = 'Data Analyst';

This command returns:

Conclusion

The OR operator is a powerful tool in SQL that allows you to retrieve records that meet at least one of multiple conditions. By using OR, you can create more flexible and inclusive queries that cater to a wider range of criteria. Understanding how to use OR in combination with other SQL clauses like AND, ORDER BY, and SELECT DISTINCT can greatly enhance your ability to work with databases.

In our next tutorial, we’ll explore more advanced SQL topics and commands. Stay tuned and happy coding!