original_string: protected function filter_by_non_letter($finalfield) {
          global $DB;
  
          $alphabet = explode(',', get_string('alphabet', 'langconfig'));
          list($nia, $aparams) = $DB->get_in_or_equal($alphabet, SQL_PARAMS_NAMED, 'nonletter', false);
  
          $sql = $DB->sql_substr(sprintf('upper(%s)', $finalfield), 1, 1);
  
          $this->where[] = "$sql $nia";
          $this->params = array_merge($this->params, $aparams);
      }
code: protected function filter_by_non_letter($finalfield) {
          global $DB;
  
          $alphabet = explode(',', get_string('alphabet', 'langconfig'));
          list($nia, $aparams) = $DB->get_in_or_equal($alphabet, SQL_PARAMS_NAMED, 'nonletter', false);
  
          $sql = $DB->sql_substr(sprintf('upper(%s)', $finalfield), 1, 1);
  
          $this->where[] = "$sql $nia";
          $this->params = array_merge($this->params, $aparams);
      }
code_tokens: protected function filter_by_non_letter ( $ finalfield ) { global $ DB ; $ alphabet = explode ( ',' , get_string ( 'alphabet' , 'langconfig' ) ) ; list ( $ nia , $ aparams ) = $ DB -> get_in_or_equal ( $ alphabet , SQL_PARAMS_NAMED , 'nonletter' , false ) ; $ sql = $ DB -> sql_substr ( sprintf ( 'upper(%s)' , $ finalfield ) , 1 , 1 ) ; $ this -> where [ ] = "$sql $nia" ; $ this -> params = array_merge ( $ this -> params , $ aparams ) ; }
docstring: Filter a field by special characters.
  
  @param string $finalfield The SQL statement representing the field.
docstring_tokens: Filter a field by special characters .