PHP PDO with foreach and fetch

Executing the same query again only to get the results you already had, as suggested in the accepted answer, is a madness. Adding some extra code to perform such a simple task also makes no sense. I have no idea why people would devise such complex and inefficient methods to complicate such primitive, most basic actions.

PDOStatement is not an array. Using foreach over a statement is just a syntax sugar that internally uses the familiar one-way while loop. If you want to loop over your data more than once, simply select it as a regular array first

$sql = "SELECT * FROM users";
$stm = $dbh->query($sql);
// here you go:
$users = $stm->fetchAll();

and then use this array as many times as you need:

foreach ($users as $row) {
    print $row["name"] . "-" . $row["sex"] ."<br/>";
}
echo "<br/>";
foreach ($users as $row) {
    print $row["name"] . "-" . $row["sex"] ."<br/>";
}

Also quit that try..catch thing. Don't use it, but set the proper error reporting for PHP and PDO

A PDOStatement (which you have in $users) is a forward-cursor. That means, once consumed (the first foreach iteration), it won't rewind to the beginning of the resultset.

You can close the cursor after the foreach and execute the statement again:

$users       = $dbh->query($sql);
foreach ($users as $row) {
    print $row["name"] . " - " . $row["sex"] . "<br/>";
}

$users->execute();

foreach ($users as $row) {
    print $row["name"] . " - " . $row["sex"] . "<br/>";
}

Or you could cache using tailored CachingIterator with a fullcache:

$users       = $dbh->query($sql);

$usersCached = new CachedPDOStatement($users);

foreach ($usersCached as $row) {
    print $row["name"] . " - " . $row["sex"] . "<br/>";
}
foreach ($usersCached as $row) {
    print $row["name"] . " - " . $row["sex"] . "<br/>";
}

You find the CachedPDOStatement class as a gist. The caching iterator is probably more sane than storing the result set into an array because it still offers all properties and methods of the PDOStatement object it has wrapped.