Method wrap_unit_into_derived

sql/sql_lex.cc:6588–6647

}

SELECT_LEX *
LEX::wrap_unit_into_derived(SELECT_LEX_UNIT *unit)
{
  SELECT_LEX *wrapping_sel;
  Table_ident *ti;
  DBUG_ENTER("LEX::wrap_unit_into_derived");

  if (!(wrapping_sel= alloc_select(TRUE)))
    DBUG_RETURN(NULL);
  Name_resolution_context *context= &wrapping_sel->context;
  context->init();
  wrapping_sel->automatic_brackets= FALSE;
  wrapping_sel->mark_as_unit_nest();
  wrapping_sel->register_unit(unit, context);

  /* stuff dummy SELECT * FROM (...) */

  if (push_select(wrapping_sel)) // for Items & TABLE_LIST
    DBUG_RETURN(NULL);

  /* add SELECT list*/
  {
    Item *item= new (thd->mem_root) Item_field(thd, context, star_clex_str);
    if (item == NULL)
      goto err;
    if (add_item_to_list(thd, item))
      goto err;
    (wrapping_sel->with_wild)++;
  }

  unit->first_select()->set_linkage(DERIVED_TABLE_TYPE);

  ti= new (thd->mem_root) Table_ident(unit);
  if (ti == NULL)
    goto err;
  {
    TABLE_LIST *table_list;
    LEX_CSTRING alias;
    if (wrapping_sel->make_unique_derived_name(thd, &alias))
      goto err;

    if (!(table_list= wrapping_sel->add_table_to_list(thd, ti, &alias,
                                                      0, TL_READ,
                                                      MDL_SHARED_READ)))
      goto err;

    context->resolve_in_table_list_only(table_list);
    wrapping_sel->add_joined_table(table_list);
  }

  pop_select();

  derived_tables|= DERIVED_SUBQUERY;

  DBUG_RETURN(wrapping_sel);

err:
  pop_select();