php - Why the PDO statement error comes in this code? -

i have following code, unable figure out why pdo statement error occurs, here code

try {         $db = new pdo("mysql:dbname=imdb","username","pwd");         $db->setattribute(pdo::attr_errmode, pdo::errmode_exception);         $first_name=$db->quote($first_name);         $last_name=$db->quote($last_name);         $row_id=$db->query("select id actors last_name=$last_name , first_name ${first_name} order film_count desc limit 1");         if ($row_id->rowcount() > 0) {             $idrow=$row_id->fetch_assoc();                 print_r($idrow);             return $row_id;         }         else {             return null;         }     }     catch (pdoexception $ex) {     ?>         <p>sorry, database error occurred. please try again later.</p>          <p>(error details: <?= $ex->getmessage() ?>)</p>     <?php         return null;     } 

i error when run

fatal error: call undefined method pdostatement::fetch_assoc()

any help?

because error says. fetch_assoc() isn't defined.

you want

$row_id->fetch(pdo::fetch_assoc) 

fetch() correct method name , pass 1 of pdo constants determine type of variable back.