original_string: final protected function where_not_null($column, $or = false){
          $this->_wheres[] = [$this->and_or($or), sprintf("%s IS NOT NULL", $this->escape_column_name($column))];
          return $this;
      }
code: final protected function where_not_null($column, $or = false){
          $this->_wheres[] = [$this->and_or($or), sprintf("%s IS NOT NULL", $this->escape_column_name($column))];
          return $this;
      }
code_tokens: final protected function where_not_null ( $ column , $ or = false ) { $ this -> _wheres [ ] = [ $ this -> and_or ( $ or ) , sprintf ( "%s IS NOT NULL" , $ this -> escape_column_name ( $ column ) ) ] ; return $ this ; }
docstring: Add where not null clause
  
  @param string $column
  @param bool $or Default false
  @return $this
docstring_tokens: Add where not null clause