Fatal error: Uncaught mysqli_sql_exception: Unknown column 'C' in 'where clause' in /home/autoitit/public_html/controller/db_function.php:22 Stack trace: #0 /home/autoitit/public_html/controller/db_function.php(22): mysqli->query('SELECT user.*, ...') #1 /home/autoitit/public_html/model/class.User.php(175): ExecQuery('SELECT user.*, ...', 'select') #2 /home/autoitit/public_html/venditore/index.php(17): User::getById('C') #3 {main} thrown in /home/autoitit/public_html/controller/db_function.php on line 22