How to Use the SQL IN Operator

SQL IN Operator Introduced

In SQL, IN is a logical operator that allows you to filter a set of values against a specific condition. It is usually used with the WHERE clause.

In the parentheses, you can define the exact values you need to be matched by the data entries:

SELECT column_demo(z)
FROM table_demo
WHERE column_demo IN (value1, value2, ...);

You can also use the SELECT statement to create a subquery that returns a list of values in a specified column:

SELECT column_demo(z)
FROM table_demo
WHERE column_demo IN (SELECT STATEMENT);

Demo Databases

In this tutorial, we will be using two demo tables for our data – Developers and Customers.

Developers

Pros

• Simplistic design (no unnecessary information)
• High-quality courses (even the free ones)
• Variety of features

Main Features

• Nanodegree programs
• Suitable for enterprises
• Paid certificates of completion

100% FREE

Pros

• Professional service
• Flexible timetables
• A variety of features to choose from

Main Features

• Professional certificates of completion
• University-level courses
• Multiple Online degree programs

100% FREE

Pros

• Great user experience
• Offers quality content
• Very transparent with their pricing

Main Features

• Free certificates of completion
• Focused on data science skills
• Flexible learning timetable

100% FREE

Customers

Examples of Using SQL IN()

The example below picks all the developers from USA, France and India:

SELECT * FROM Developers
WHERE Country IN ('USA', 'France', 'India');

For an opposite result, you can also use the NOT IN operator in SQL. The code in this next example picks out only the developers who are not from those countries:

SELECT * FROM Developers
WHERE Country NOT IN ('USA', 'France', 'India');

Working with IN() in Multiple Tables

In the last example, we will try something a bit more complicated. The code you can see below uses both of our demo tables to pick all the developers whose countries match those of the customers:

SELECT * FROM Developers
WHERE Country IN (SELECT Country FROM Customers);

Instead of specifying the values for SQL IN(), we include SELECT Country FROM Customers within the parentheses. This means the SELECT statement will take the values from the Country column in the Customers table.