Method add_fields

sql/sql_select.cc:22214–22434

bool Create_tmp_table::add_fields(THD *thd,
                                  TABLE *table,
                                  TMP_TABLE_PARAM *param,
                                  List<Item> &fields)
{
  DBUG_ENTER("Create_tmp_table::add_fields");
  DBUG_ASSERT(table);
  DBUG_ASSERT(table->field);
  DBUG_ASSERT(table->s->blob_field);
  DBUG_ASSERT(table->s->reclength == 0);
  DBUG_ASSERT(table->s->fields == 0);
  DBUG_ASSERT(table->s->blob_fields == 0);

  const bool not_all_columns= !(m_select_options & TMP_TABLE_ALL_COLUMNS);
  bool distinct_record_structure= m_distinct;
  uint fieldnr= 0;
  TABLE_SHARE  *share= table->s;
  Item **copy_func= param->items_to_copy;

  MEM_ROOT *mem_root_save= thd->mem_root;
  thd->mem_root= &table->mem_root;

  List_iterator_fast<Item> li(fields);
  Item *item;
  Field **tmp_from_field= m_from_field;
  while (!m_with_cycle && (item= li++))
    if (item->is_in_with_cycle())
    {
      m_with_cycle= true;
      /*
        Following distinct_record_structure is (m_distinct || m_with_cycle)

        Note: distinct_record_structure can be true even if m_distinct is
        false, for example for incr_table in recursive CTE
        (see select_union_recursive::create_result_table)
      */
      distinct_record_structure= true;
    }
  li.rewind();
  while ((item=li++))
  {
    uint uneven_delta;
    current_counter= (((param->hidden_field_count < (fieldnr + 1)) &&
                       distinct_record_structure &&
                       (!m_with_cycle || item->is_in_with_cycle())) ?
                      distinct :
                      other);
    Item::Type type= item->type();
    if (type == Item::COPY_STR_ITEM)
    {
      item= ((Item_copy *)item)->get_item();
      type= item->type();
    }
    if (not_all_columns)
    {
      if (item->with_sum_func() && type != Item::SUM_FUNC_ITEM)
      {
        if (item->used_tables() & OUTER_REF_TABLE_BIT)