Method append

sql/item.h:2160–2164

  bool basic_const_item() const { return 1; }

  inline void append(char *str, uint length)
  {
    str_value.append(str, length);
    max_length= str_value.numchars() * collation.collation->mbmaxlen;
  }
  virtual void print(String *str, enum_query_type query_type);
  bool check_partition_func_processor(uchar *int_arg) {return FALSE;}