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/* Copyright (C) 2000 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/*
Derived tables
These were introduced by Monty and Sinisa <sinisa@mysql.com>
*/
#include "mysql_priv.h"
#include "sql_select.h"
#include "sql_acl.h"
static const char *any_db="*any*"; // Special symbol for check_access
int mysql_derived(THD *thd, LEX *lex, SELECT_LEX_UNIT *unit, TABLE_LIST *t)
{
/*
TODO: make derived tables with union inside (now only 1 SELECT may be
procesed)
*/
SELECT_LEX *sl= unit->first_select();
List<Item> item_list;
TABLE *table;
int res= 0;
select_union *derived_result;
TABLE_LIST *tables= (TABLE_LIST *)sl->table_list.first;
TMP_TABLE_PARAM tmp_table_param;
DBUG_ENTER("mysql_derived");
if (tables)
res= check_table_access(thd,SELECT_ACL, tables);
else
res= check_access(thd, SELECT_ACL, any_db);
if (res)
DBUG_RETURN(-1);
for (SELECT_LEX *ssl= sl; ssl; ssl= ssl->next_select_in_list())
{
TABLE_LIST *t_tables= (TABLE_LIST *)ssl->table_list.first;
for (TABLE_LIST *cursor= (TABLE_LIST *)t_tables;
cursor;
cursor=cursor->next)
{
if (cursor->derived)
{
res= mysql_derived(thd, lex, (SELECT_LEX_UNIT *)cursor->derived,
cursor);
if (res) DBUG_RETURN(res);
}
}
}
Item *item;
List_iterator<Item> it(sl->item_list);
while ((item= it++))
item_list.push_back(item);
if (!(res=open_and_lock_tables(thd,tables)))
{
if (setup_fields(thd,tables,item_list,0,0,1))
{
res=-1;
goto exit;
}
bzero((char*) &tmp_table_param,sizeof(tmp_table_param));
tmp_table_param.field_count=item_list.elements;
if (!(table=create_tmp_table(thd, &tmp_table_param, item_list,
(ORDER*) 0, 0, 1, 0,
(sl->options | thd->options |
TMP_TABLE_ALL_COLUMNS),
unit)))
{
res=-1;
goto exit;
}
if ((derived_result=new select_union(table)))
{
derived_result->tmp_table_param=&tmp_table_param;
unit->offset_limit_cnt= sl->offset_limit;
unit->select_limit_cnt= sl->select_limit+sl->offset_limit;
if (unit->select_limit_cnt < sl->select_limit)
unit->select_limit_cnt= HA_POS_ERROR;
if (unit->select_limit_cnt == HA_POS_ERROR)
sl->options&= ~OPTION_FOUND_ROWS;
SELECT_LEX_NODE *save_current_select= lex->current_select;
lex->current_select= sl;
res= mysql_select(thd, tables, sl->item_list,
sl->where, (ORDER *) sl->order_list.first,
(ORDER*) sl->group_list.first,
sl->having, (ORDER*) NULL,
sl->options | thd->options | SELECT_NO_UNLOCK,
derived_result, unit, sl, 0);
lex->current_select= save_current_select;
if (!res)
{
// Here we entirely fix both TABLE_LIST and list of SELECT's as there were no derived tables
if (derived_result->flush())
res=1;
else
{
t->real_name=table->real_name;
t->table=table;
table->derived_select_number= sl->select_number;
table->tmp_table=TMP_TABLE;
if (!lex->describe)
sl->exclude();
t->db=(char *)"";
t->derived=(SELECT_LEX *)0; // just in case ...
}
}
delete derived_result;
}
if (res)
free_tmp_table(thd,table);
exit:
close_thread_tables(thd);
}
DBUG_RETURN(res);
}
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