Function do_select

sql/sql_select.cc:24099–24299

*/

static int
do_select(JOIN *join, Procedure *procedure)
{
  int rc= 0;
  enum_nested_loop_state error= NESTED_LOOP_OK;
  uint top_level_tables= join->exec_join_tab_cnt();
  DBUG_ENTER("do_select");

  if (join->pushdown_query)
  {
    /* Select fields are in the temporary table */
    join->fields= &join->tmp_fields_list1;
    /* Setup HAVING to work with fields in temporary table */
    join->set_items_ref_array(join->items1);
    /* The storage engine will take care of the group by query result */
    int res= join->pushdown_query->execute(join);

    if (res)
      DBUG_RETURN(res);

    if (join->pushdown_query->store_data_in_temp_table)
    {
      JOIN_TAB *last_tab= join->join_tab + top_level_tables;
      last_tab->next_select= end_send;
      last_tab->cached_pfs_batch_update= last_tab->pfs_batch_update();

      enum_nested_loop_state state= last_tab->aggr->end_send();
      if (state >= NESTED_LOOP_OK)
        state= sub_select(join, last_tab, true);

      if (state < NESTED_LOOP_OK)
        res= 1;

      if (join->result->send_eof())
        res= 1;
    }
    DBUG_RETURN(res);
  }
  
  join->procedure= procedure;
  join->duplicate_rows= join->send_records=0;

  if (join->only_const_tables() && !join->need_tmp)
  {
    Next_select_func end_select= setup_end_select_func(join);

    /*
      HAVING will be checked after processing aggregate functions,
      But WHERE should checked here (we alredy have read tables).
      Notice that make_join_select() splits all conditions in this case
      into two groups exec_const_cond and outer_ref_cond.
      If join->table_count == join->const_tables then it is
      sufficient to check only the condition pseudo_bits_cond.
    */
    DBUG_ASSERT(join->outer_ref_cond == NULL);
    if (!join->pseudo_bits_cond || join->pseudo_bits_cond->val_bool())
    {
      // HAVING will be checked by end_select