How to remove the prefix of the connected table through db_select?

Question

Drupal

Good morning gurus!
Actually a question.

$query = db_select('user_discounts', 'u'); 
  $query->fields('user_discounts', array('CardNum'));
  $result = $query->execute();

As a result I get

PDOException: SQLSTATE[42S02]: Base table or view not found: 1146 Table namedatabase.prefix_user_discounts ' doesn't exist

For all that, the plate is custom and there is no prefix in it. But the system automatically tries to add it and of course I can’t connect to it.
P.S. in settings.php did not register the default prefix.
Thank you very much =)

Answer 1

if this is not a Drupal table, then the function must be used not Drupal
IMHO