How can the PHP manual be utilized to improve understanding and usage of PHP functions like mysql_query()?

To improve understanding and usage of PHP functions like mysql_query(), one can refer to the PHP manual for detailed documentation, examples, and explanations of the function's parameters and return values. This can help clarify how to properly use the function and handle any errors or issues that may arise.

$query = "SELECT * FROM users";
$result = mysql_query($query);

if (!$result) {
    die('Invalid query: ' . mysql_error());
}

// Process the result set here