What are the key differences between mysqli_query() and mysql_query() functions in PHP and how should they be utilized for database operations?

The key difference between mysqli_query() and mysql_query() functions in PHP is that mysqli_query() is used with the improved MySQL extension (MySQLi), while mysql_query() is used with the deprecated MySQL extension. It is recommended to use mysqli_query() for database operations as it provides enhanced security features and support for prepared statements.

// Example of utilizing mysqli_query() for database operations
$connection = mysqli_connect("localhost", "username", "password", "database");

$query = "SELECT * FROM table";
$result = mysqli_query($connection, $query);

if($result){
    while($row = mysqli_fetch_assoc($result)){
        // Process data here
    }
} else {
    echo "Error: " . mysqli_error($connection);
}

mysqli_close($connection);