Item_sum_hybrid::fix_fields(THD *thd, Item **ref)

{

...

  Type_std_attributes::set(args[0]);

...

  Item *item2= item->real_item();

  if (item2->type() == Item::FIELD_ITEM)

    set_handler_by_field_type(((Item_field*) item2)->field->type());

  else if (item->cmp_type() == TIME_RESULT)

    set_handler_by_field_type(item2->field_type());

  else

    set_handler_by_result_type(item2->result_type(),

                               max_length, collation.collation);

  switch (Item_sum_hybrid::result_type()) {

  case INT_RESULT:

  case DECIMAL_RESULT:

  case STRING_RESULT:

    break;

  case REAL_RESULT:

    max_length= float_length(decimals);

    break;

  case ROW_RESULT:

  case TIME_RESULT:

    DBUG_ASSERT(0);

  };

  setup_hybrid(thd, args[0], NULL);

  /* MIN/MAX can return NULL for empty set indepedent of the used column */

  maybe_null= 1;

  result_field=0;

  null_value=1;

  fix_length_and_dec();

...

}

bool Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const;

args[0]->type_handler()->Item_sum_hybrid_fix_length_and_dec(this);