Question

I’ve used PDO in my PHP application. But I have problem with fetch() function. Whenever I count the result of fetch(), it tells me there is something in resultset. But when I want to show them, it has nothing to show.

try
{ 
    $sql = "SELECT id,salt FROM tbl_admin WHERE username = ? AND password = ? LIMIT 1";
    $q = $db->prepare($sql);
    $q->execute(array($username,$password));
    $rows = $q->columnCount();

    if ($rows > 0)
    {
        $r = $q->fetch(PDO::FETCH_BOTH);
        echo(count($r).'<br />'); // Prints 1
        print_r($r); // Nothing to print ...
        die();
    }
    else
    {
        die('error');
    }
}
catch(PDOException $e)
{
    echo $e->getMessage();
}

May you help me please?

Answer 1

You’re counting the number of columns, not the number of rows.

$rows = $q->columnCount();

This should be

$rows = $q->rowCount();

---

That said, rowCount is for UPDATE, INSERT, or DELETE queries. So that isn’t the problem here.

Firstly should also be checking if $q->execute returns true or false.

Secondly you should be checking if $q->fetch returns true or false.

Given your code

$r = $q->fetch(PDO::FETCH_BOTH);
echo(count($r).'<br />'); // Prints 1

Try the following.

echo(count(false));

You’ll notice that this also outputs 1.

So the solution is, that you need to check the return value of $q->fetch before assuming it returned a valid row.