Problem in MySql query on WordPress [closed]

I think the problem is here

{$wpdb->prefix}prflxtrflds_user_field_data

It seems your {$wpdb->prefix} value is prflxtrflds

So you can directly use :

global $wpdb;
$results = $wpdb->get_results( "SELECT user_id FROM {$wpdb->prefix}user_field_data WHERE id = 37" );`

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)