Checking result/count before outputting while loop - php

Question

I'm looking for a way to SELECT from database, then check the result, and then output rows in a while loop (IF the result was above zero)
I really want to avoid using a separate count query
Right now I use this:
$sql = 'SELECT id, username, usercity, usercountry FROM siteusers WHERE userage > 50';
$STH = $conn->query($sql);
$arr = $STH->fetchAll();
if (count($arr) > 0) {
echo '<div id="users">';
foreach ($arr as $row) {
echo '<h1>'.$row['username'].</h1>';
}
echo '</div>';
}
It works. But isn't there a way I can check result/numrows and loop the rows, without using fetchAll and custom for-each loop?
Or does it not matter at all? (is for-each just as good as while loop?)
If I do it like this, the first row is not included in the while loop:
$sql = 'SELECT id, username, usercity, usercountry FROM siteusers WHERE userage > 50';
$STH = $conn->query($sql);
if ($row = $STH->fetch()) {
echo '<div id="users">';
while ($row = $STH->fetch()) {
echo '<h1>'.$row['username'].</h1>';
}
echo '</div>';
}
EDIT: I DO need to check the result, for dynamic layout purposes

Answer 1

You can use the PDO method rowCount to verify before your foreach if there are rows
$STH = $conn->query($sql);
if ($STH->rowCount())
{echo '<div id="users">';
foreach ($STH->fetchAll() as $row)
{
echo '<h1>'.$row['username'].'</h1>';
}
echo '</div>';
}
http://php.net/manual/en/pdostatement.rowcount.php
note that this uses up a lot of memory as all your results are loaded at once in memory with fetchAll(). if you have very large result sets, consider using a while instead of the foreach
while ($row = $STH->fetch())
{// foo with $row
}

Answer 2

$row is being set to the first row of your results inside of your if statement. This means that your while loop will start at the second row.
$sql = 'SELECT id, username, usercity, usercountry FROM siteusers WHERE userage > 50';
$STH = $conn->query($sql);
echo '<div id="users">';
while ($row = $STH->fetch()) {
echo '<h1>'.$row['username'].</h1>';
}
echo '</div>';
The while loop will run if there is any results to fetch, and if there aren't, then respectively it won't run.