What are the potential pitfalls of using null values in PHP variables?

Using null values in PHP variables can lead to potential pitfalls such as unexpected behavior when performing operations on these variables, difficulty in debugging code due to unexpected null values, and potential security vulnerabilities if null values are not properly handled. To avoid these pitfalls, it is important to always check for null values before using them in operations or functions.

// Check for null value before using the variable
$variable = null;

if ($variable !== null) {
    // Perform operations on the variable
    echo $variable;
} else {
    // Handle null value
    echo "Variable is null";
}