Commit 3b6546b8 authored by Sinisa@sinisa.nasamreza.org's avatar Sinisa@sinisa.nasamreza.org
Browse files

EXPLAIN on UNION"s

parent 66b4a894

mysql-test/r/union.result

+3 −0
Original line number Diff line number Diff line
@@ -56,3 +56,6 @@ t2 c 1 
t2	d	1

t2	e	1

t2	f	1

table	type	possible_keys	key	key_len	ref	rows	Extra

t1	ALL	NULL	NULL	NULL	NULL	4	

t2	ALL	NULL	NULL	NULL	NULL	4

mysql-test/t/union.test

+0 −1
Original line number Diff line number Diff line
@@ -17,7 +17,6 @@ select a,b from t1 union select a,b from t1; 
select 't1',b,count(*) from t1 group by b UNION select 't2',b,count(*) from t2 group by b;



# Test some error conditions with UNION

--error 1215

explain select a,b from t1 union all select a,b from t2;



--error 1215

sql/sql_select.cc

+20 −17
Original line number Diff line number Diff line
@@ -6752,6 +6752,8 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order, 


  /* Don't log this into the slow query log */

  join->thd->lex.select_lex.options&= ~(QUERY_NO_INDEX_USED | QUERY_NO_GOOD_INDEX_USED);

  if (join->thd->lex.select == &join->thd->lex.select_lex)

  {

    field_list.push_back(new Item_empty_string("table",NAME_LEN));

    field_list.push_back(new Item_empty_string("type",10));

    field_list.push_back(item=new Item_empty_string("possible_keys",
@@ -6767,8 +6769,8 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order, 
    field_list.push_back(new Item_real("rows",0.0,0,10));

    field_list.push_back(new Item_empty_string("Extra",255));

    if (send_fields(thd,field_list,1))

    return; /* purecov: inspected */



      return;

  }

  char buff[512],*buff_ptr;

  String tmp(buff,sizeof(buff)),*packet= &thd->packet;

  table_map used_tables=0;
@@ -6899,6 +6901,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order, 
    // For next iteration

    used_tables|=table->map;

  }

  if (!join->thd->lex.select->next)

    send_eof(&thd->net);

  DBUG_VOID_RETURN;

}

sql/sql_union.cc

+19 −6
Original line number Diff line number Diff line
@@ -38,12 +38,6 @@ int mysql_union(THD *thd, LEX *lex,select_result *result) 
  uint elements;

  DBUG_ENTER("mysql_union");



  if (lex->select_lex.options & SELECT_DESCRIBE)

  {

    my_error(ER_WRONG_USAGE,MYF(0),"DESCRIBE","UNION");

    return -1;

  } 



  /* Fix tables--to-be-unioned-from list to point at opened tables */

  for (sl=&lex->select_lex; sl; sl=sl->next)

  {
@@ -66,6 +60,25 @@ int mysql_union(THD *thd, LEX *lex,select_result *result) 
    }

  }



  if (lex->select_lex.options & SELECT_DESCRIBE)

  {

    for (sl= &lex->select_lex; sl; sl=sl->next)

    {

      lex->select=sl;

      res=mysql_select(thd, (TABLE_LIST*) sl->table_list.first,

		       sl->item_list,

		       sl->where,

		       sl->ftfunc_list,

		       (ORDER*) 0,

		       (ORDER*) sl->group_list.first,

		       sl->having,

		       (ORDER*) NULL,

		       sl->options | thd->options | SELECT_NO_UNLOCK | SELECT_DESCRIBE,

		       result);

    }

    return 0;

  } 



  order = (ORDER *) last_sl->order_list.first;

  {

    Item *item;