Select Query with a condition , Limit and Order By Clause Drupal 7

$query = db_select('opinions','o')->fields('o')->condition('approved','Yes','=')->condition('bid',$node->nid,'=')->orderBy('opinion_id', 'DESC')->range(0,3); 
$result = $query->execute();
$row = $result->fetchAssoc();
print_r(($row); // to view all fields name
print $row['uid'];