Named DB Sequence Generators (WordPress)

function getNextSequenceNumber($sequenceName)
{
    global $wpdb;

    $wpdb->query($wpdb->prepare(
        "
            INSERT INTO table_name
            (seq_name, seq_num)
            VALUES (%s, LAST_INSERT_ID(1))
            ON DUPLICATE KEY UPDATE seq_num = LAST_INSERT_ID(seq_num + 1);
        ",
        $seq_name
    ));

    return $wpdb->get_var("SELECT LAST_INSERT_ID();");
}