To close a connection to a MySQL database in PHP, you can use the mysqli_close function like mysqli_close(______);.

To close a connection to a MySQL database in PHP using the mysqli extension, you would use the mysqli_close function. It takes the connection object ($conn) as a parameter and closes the database connection. Ensure you pass the correct connection object to mysqli_close (e.g., $conn) to close the connection properly. Although PHP automatically closes the connection at the end of the script execution, it's good practice to explicitly close the connection when you no longer need it to free up resources.