Group MySQL results into blocks of A-Z in PHP - php

Question

I have a list of thousands of results and I want to group them alphanumerically for example, I need it to be like this:
<h1>0-9</h1>
<ul>
<li>011example</li>
<li>233example</li>
<li>65example</li>
</ul>
<h1>A</h1>
<ul>
<li>albert</li>
<li>alfred</li>
<li>annie</li>
</ul>
<h1>B</h1>
<ul>
<li>ben</li>
<li>bertie</li>
<li>burt</li>
</ul>
But I can't work out how to split or group my results into 0-9 and A-Z.
Currently I have:
<?php
$get_az = mysql_query("SELECT custom_22 FROM db_table1");
echo '<ul>';
while ($row = mysql_fetch_assoc($get_az)) {
$getfirstletter = substr($row['custom_22'], 0,1);
$name = $row['custom_22'];
echo '<h1>'.$getfirstletter.'</h1>';
echo '<li>'.$name.'</li>';
}
echo '</ul>';
?>

Answer 1

Order by the name and handle each letter one by one.
$get_az = mysql_query("SELECT custom_22 FROM db_table1 ORDER BY custom_22 ASC");
$current_first_letter = null;
while ($row = mysql_fetch_assoc($get_az)) {
$first_letter = strtolower(substr($row['custom_22'], 0, 1));
if (preg_match("/[0-9]/", $first_letter)) { // detect digits
$first_letter = "0-9";
}
if ($first_letter !== $current_first_letter) {
if ($current_first_letter !== null) {
echo '</ul>';
}
echo '<h1>' . $first_letter . '</h1>';
echo '<ul>';
}
$current_first_letter = $first_letter;
echo '<li>' . htmlentities($row['custom_22']) . '</li>';
}
if ($current_first_letter !== null) {
echo '</ul>';
}

Answer 2

I would do it this readable way:
$get_az = mysql_query('SELECT custom_22 FROM db_table1 ORDER BY custom_22');
$groups = array();
split results to groups
while ($row = mysql_fetch_assoc($get_az)) {
$firstLetter = strtolower(substr($row['custom_22'], 0, 1));
check for digits
if (is_numeric($firstLetter)) {
$firstLetter = '0-9';
}
if (isset($groups[$firstLetter]) === false) {
$groups[$firstLetter] = array();
}
$groups[$firstLetter][] = $row['custom_22'];
}
simply iterate over groups and echoes it
foreach ($groups as $h1 => $items) {
echo sprintf('<h1>%s</h1>', strtoupper(htmlspecialchars($h1)));
echo '<ul>';
foreach ($items as $item) {
echo sprintf('<li>%s</li>', htmlspecialchars($item));
}
echo '</ul>';
}