Select all where [first letter starts with B]

This is a follow up question to my previous one. I want to write a MYSQL statement that echoes every entry that starts with letter B.

Function.php

function getCategory() {
$query = mysql_query("SELECT author FROM lyrics WHERE author [starts with letter B]") or die(mysql_error());
while ($row = mysql_fetch_assoc($query)) { ?>
    <p><a href="##"><?= $row['author']; ?></a></p>
    <?php }

Category.php?category=b

<?php include 'includes/header.php' ?>
<?php getCategory(); ?>
<?php include 'includes/footer.php' ?>

Like that I guess. And then one for every letter of the alphabet, and one with misc (numbers etc)