The MySQL IN Operator
The IN operator is used in the WHERE clause to check if a specified column's value matches any value within a provided list.
The IN operator functions as a shorthand for multiple OR conditions, making queries shorter and more readable.
IN Syntax
SELECT column_name(s)
FROM table_name
WHERE column_name IN (value1, value2, ...);
Demo Database
Below is a selection from the "Customers" table in the Northwind sample database:
| CustomerID | CustomerName | ContactName | Address | City | PostalCode | Country |
|---|---|---|---|---|---|---|
| 1 | Alfreds Futterkiste | Maria Anders | Obere Str. 57 | Berlin | 12209 | Germany |
| 2 | Ana Trujillo Emparedados y helados | Ana Trujillo | Avda. de la Constitución 2222 | México D.F. | 05021 | Mexico |
| 3 | Antonio Moreno Taquería | Antonio Moreno | Mataderos 2312 | México D.F. | 05023 | Mexico |
| 4 | Around the Horn | Thomas Hardy | 120 Hanover Sq. | London | WA1 1DP | UK |
| 5 | Berglunds snabbköp | Christina Berglund | Berguvsvägen 8 | Luleå | S-958 22 | Sweden |
IN Operator Example
The following SQL uses the IN operator to select all customers from Germany, France, or UK:
Example
SELECT * FROM Customers
WHERE Country IN ('Germany', 'France', 'UK');
The NOT IN Operator
By using the NOT IN operator, you return all records that are NOT any of the values in the list.
The following SQL selects all customers that are NOT located in "Germany", "France" or "UK":
Example
SELECT * FROM Customers
WHERE Country NOT IN ('Germany', 'France', 'UK');
IN (SELECT)
You can also use IN with a subquery in the WHERE clause.
With a subquery you can return all records from the main query that are present in the result of the subquery.
The following SQL returns all customers who also have an order in the "Orders" table:
Example
SELECT * FROM Customers
WHERE CustomerID IN (SELECT CustomerID FROM Orders);
NOT IN (SELECT)
The result in the example above returned 89 records, that means that there are 2 customers that haven't placed any orders.
Let us check if that is correct, by using the NOT IN operator.
The following SQL returns all customers who do NOT have any orders in the "Orders" table:
Example
SELECT * FROM Customers
WHERE CustomerID NOT IN (SELECT CustomerID FROM Orders);
