PHP PDO提取类返回FALSE

Question

I have this PHP function that gets the data of the currently logged in user, or returns false if the visitor either isn't logged in, or has invalid user_id and password_hash cookies. For some reason, $q->fetch() always returns FALSE.

if( $_COOKIE['cuid']!='' && $_COOKIE['cuph']!='' )
{
    try
    {
        $q = $db->prepare( 'SELECT * FROM users WHERE user_id = ? AND password = ?' );
        $data = array( $_COOKIE['cuid'], $_COOKIE['cuph'] ); // id and password hash
        $q->execute($data);
        $num = count( $q->fetchAll() ); // in my case, $num is set to 1
        if( $num == 1 )
        {
            $q->setFetchMode(PDO::FETCH_CLASS, 'User');
            $user = $q->fetch(); // $user is set to FALSE for some reason
            return $user;
        } else {
            return FALSE;
        }
    }
    catch( Exception $e )
    {
        $db->rollBack();
        echo 'Error: ' . $e->getMessage();
    }
} else {
    return FALSE;
}

Running that with exact data instead of placeholders in the query doesn't change anything, and running that query directly in my database returns 1 row, like it should. I checked, $num does indeed equal 1. I don't know why $q->fetch() returns FALSE, so any pointers would be very much appreciated.

Answer 1

You're already fetching all results using fetchAll() . The result set is thereby exhausted, you cannot fetch any more results from it. You simply want $q->rowCount() to count the rows or save the array returned by fetchAll() somewhere and use it later.

Answer 2

As said, you cannot use fetchAll then fetch after one query; but rowCount cannot be used for select. A solution can be:

You get results in an array with fetchAll:

$results=$q->fetchAll()

Then you can get and use or check the number, for example:

echo count( $results);

And get and work with results, for example:

foreach ($results as $result)
{
   var_dump($result);
}