使用php表中的查询结果填写下拉列表

Question

我一直在尝试使用来自mysql表的php查询结果填充下拉列表，但列表为空。有人可以看看我的代码并告诉我，我做错了什么。

我的查询是Select cat from kernel

我使用了代码：$results = $query->fetchAll();

继承我的代码：

<?php

$dbhandle = new PDO('host','username','password');


$sql = "SELECT cat FROM kernel";
$results = $query->fetchAll();

echo "<select name='cat'>";
while ($row = mysql_fetch_array($result)) {
echo "<option value='" . $row['cat'] . "'>" . $row['cat'] . "</option>";
}
echo "</select>";

?>

Answer 1

<?php

$sth = $dbhandle->prepare("SELECT cat FROM kernel");
$sth->execute();
$results = $sth->fetchAll(PDO::FETCH_ASSOC);

echo "<select name='cat'>";
foreach($results as $row) {
    echo "<option value='" . $row['cat'] . "'>" . $row['cat'] . "</option>";
}    
echo "</select>";

?>

http://us2.php.net/manual/en/pdostatement.fetchall.php