Question

My Database

id  username
1   xxx
2   bbb
3   vvv
4   bbbbbb

i need output as

array('xxx','bbb','vvv','bbbbb');

Using PDO i need to fetch username from db & make that to array, is to for checking username exists

Answer 1

If you’re only checking if a username exist, it would be optimal to modify your query to do just that, instead of returning excess data:

$query = $pdo->prepare("SELECT `id` FROM `users` WHERE `username` = ? LIMIT 1");
$query->execute(array($username_to_test));

if ($query->rowCount() == 1)
{
    // user exists in table
}

If you do happen to need an array of usernames, do something like the following:

$usernames = array();
$query = $pdo->query("SELECT `username` FROM `users`");
while(($row = $query->fetchObject()) != null)
    $usernames[] = $row->username;