PHP: "->" not working on mysql resultset -

i have strange behaviour. untilo today using -> retrieve member variables mysql resultset, such

$username = $result->user_name 

but not working in current project.

$sth = self::$dbconnection->prepare("select user_id, user_name users");                               $sth->execute(); $result = $sth->fetch();  $test = $result->user_password_hash; // $test null  $test = $result["user_password_hash"]; // works 

????

after fixing parse error, if want object:

$result = $sth->fetch(pdo::fetch_obj); 

or:

$result = $sth->fetchobject(); 

or set mode before using fetch():

$sth->setfetchmode(pdo::fetch_obj);