mirror of
https://github.com/MariaDB/server.git
synced 2025-01-16 20:12:31 +01:00
256 lines
7.3 KiB
C++
256 lines
7.3 KiB
C++
/* Copyright (C) 2000 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/*
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UNION of select's
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UNION's were introduced by Monty and Sinisa <sinisa@mysql.com>
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*/
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#include "mysql_priv.h"
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#include "sql_select.h"
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int mysql_union(THD *thd, LEX *lex,select_result *result)
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{
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SELECT_LEX *sl;
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SELECT_LEX_UNIT *unit= &(lex->unit);
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List<Item> item_list;
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TABLE *table;
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int describe=(lex->select_lex.options & SELECT_DESCRIBE) ? 1 : 0;
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int res;
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bool found_rows_for_union=false;
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TABLE_LIST result_table_list;
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TABLE_LIST *first_table=(TABLE_LIST *)lex->select_lex.table_list.first;
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TMP_TABLE_PARAM tmp_table_param;
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select_union *union_result;
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DBUG_ENTER("mysql_union");
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st_select_lex_node * global;
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/* Fix tables 'to-be-unioned-from' list to point at opened tables */
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for (sl= &lex->select_lex;
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sl;
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sl= (SELECT_LEX *) sl->next)
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{
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for (TABLE_LIST *cursor= (TABLE_LIST *)sl->table_list.first;
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cursor;
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cursor=cursor->next)
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cursor->table= ((TABLE_LIST*) cursor->table)->table;
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}
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/* Global option */
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if (((void*)(global= unit->global_parameters)) == ((void*)unit))
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{
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found_rows_for_union = lex->select_lex.options & OPTION_FOUND_ROWS &&
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!describe && global->select_limit;
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if (found_rows_for_union)
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lex->select_lex.options ^= OPTION_FOUND_ROWS;
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}
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if (describe)
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{
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Item *item;
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item_list.push_back(new Item_empty_string("table",NAME_LEN));
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item_list.push_back(new Item_empty_string("type",10));
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item_list.push_back(item=new Item_empty_string("possible_keys",
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NAME_LEN*MAX_KEY));
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item->maybe_null=1;
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item_list.push_back(item=new Item_empty_string("key",NAME_LEN));
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item->maybe_null=1;
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item_list.push_back(item=new Item_int("key_len",0,3));
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item->maybe_null=1;
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item_list.push_back(item=new Item_empty_string("ref",
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NAME_LEN*MAX_REF_PARTS));
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item->maybe_null=1;
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item_list.push_back(new Item_real("rows",0.0,0,10));
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item_list.push_back(new Item_empty_string("Extra",255));
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}
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else
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{
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Item *item;
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List_iterator<Item> it(lex->select_lex.item_list);
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TABLE_LIST *first_table= (TABLE_LIST*) lex->select_lex.table_list.first;
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/* Create a list of items that will be in the result set */
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while ((item= it++))
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if (item_list.push_back(item))
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DBUG_RETURN(-1);
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if (setup_fields(thd,first_table,item_list,0,0,1))
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DBUG_RETURN(-1);
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}
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bzero((char*) &tmp_table_param,sizeof(tmp_table_param));
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tmp_table_param.field_count=item_list.elements;
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if (!(table= create_tmp_table(thd, &tmp_table_param, item_list,
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(ORDER*) 0, !describe & !lex->union_option,
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1, 0,
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(lex->select_lex.options | thd->options |
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TMP_TABLE_ALL_COLUMNS),
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unit)))
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DBUG_RETURN(-1);
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table->file->extra(HA_EXTRA_WRITE_CACHE);
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table->file->extra(HA_EXTRA_IGNORE_DUP_KEY);
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bzero((char*) &result_table_list,sizeof(result_table_list));
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result_table_list.db= (char*) "";
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result_table_list.real_name=result_table_list.name=(char*) "union";
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result_table_list.table=table;
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if (!(union_result=new select_union(table)))
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{
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res= -1;
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goto exit;
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}
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union_result->save_time_stamp=!describe;
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for (sl= &lex->select_lex; sl; sl= (SELECT_LEX*) sl->next)
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{
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lex->select=sl;
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unit->offset_limit_cnt= sl->offset_limit;
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unit->select_limit_cnt= sl->select_limit+sl->offset_limit;
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if (unit->select_limit_cnt < sl->select_limit)
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unit->select_limit_cnt= HA_POS_ERROR; // no limit
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if (unit->select_limit_cnt == HA_POS_ERROR)
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sl->options&= ~OPTION_FOUND_ROWS;
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res= mysql_select(thd,
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(describe && sl->linkage==GLOBAL_OPTIONS_TYPE) ?
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first_table : (TABLE_LIST*) sl->table_list.first,
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sl->item_list,
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sl->where,
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(sl->braces) ?
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(ORDER *)sl->order_list.first : (ORDER *) 0,
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(ORDER*) sl->group_list.first,
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sl->having,
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(ORDER*) NULL,
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sl->options | thd->options |
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SELECT_NO_UNLOCK | ((describe) ? SELECT_DESCRIBE : 0),
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union_result, unit);
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if (res)
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goto exit;
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}
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if (union_result->flush())
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{
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res= 1; // Error is already sent
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goto exit;
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}
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delete union_result;
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/* Send result to 'result' */
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lex->select = &lex->select_lex;
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res =-1;
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{
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/* Create a list of fields in the temporary table */
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List_iterator<Item> it(item_list);
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Field **field;
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#if 0
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List<Item_func_match> ftfunc_list;
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ftfunc_list.empty();
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#else
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thd->lex.select_lex.ftfunc_list.empty();
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#endif
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for (field=table->field ; *field ; field++)
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{
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(void) it++;
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(void) it.replace(new Item_field(*field));
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}
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if (!thd->fatal_error) // Check if EOM
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{
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st_select_lex_node * global= unit->global_parameters;
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unit->offset_limit_cnt= global->offset_limit;
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unit->select_limit_cnt= global->select_limit+global->offset_limit;
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if (unit->select_limit_cnt < global->select_limit)
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unit->select_limit_cnt= HA_POS_ERROR; // no limit
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if (unit->select_limit_cnt == HA_POS_ERROR)
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thd->options&= ~OPTION_FOUND_ROWS;
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if (describe)
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unit->select_limit_cnt= HA_POS_ERROR; // no limit
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res= mysql_select(thd,&result_table_list,
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item_list, NULL,
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(describe) ? 0 : (ORDER*)global->order_list.first,
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(ORDER*) NULL, NULL, (ORDER*) NULL,
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thd->options, result, unit);
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if (found_rows_for_union && !res)
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thd->limit_found_rows = (ulonglong)table->file->records;
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}
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}
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exit:
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free_tmp_table(thd,table);
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DBUG_RETURN(res);
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}
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/***************************************************************************
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** store records in temporary table for UNION
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***************************************************************************/
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select_union::select_union(TABLE *table_par)
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:table(table_par)
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{
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bzero((char*) &info,sizeof(info));
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/*
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We can always use DUP_IGNORE because the temporary table will only
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contain a unique key if we are using not using UNION ALL
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*/
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info.handle_duplicates= DUP_IGNORE;
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}
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select_union::~select_union()
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{
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}
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int select_union::prepare(List<Item> &list, SELECT_LEX_UNIT *u)
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{
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unit= u;
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if (save_time_stamp && list.elements != table->fields)
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{
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my_message(ER_WRONG_NUMBER_OF_COLUMNS_IN_SELECT,
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ER(ER_WRONG_NUMBER_OF_COLUMNS_IN_SELECT),MYF(0));
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return -1;
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}
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return 0;
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}
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bool select_union::send_data(List<Item> &values)
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{
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if (unit->offset_limit_cnt)
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{ // using limit offset,count
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unit->offset_limit_cnt--;
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return 0;
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}
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fill_record(table->field,values);
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return write_record(table,&info) ? 1 : 0;
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}
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bool select_union::send_eof()
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{
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return 0;
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}
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bool select_union::flush()
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{
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int error;
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if ((error=table->file->extra(HA_EXTRA_NO_CACHE)))
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{
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table->file->print_error(error,MYF(0));
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::send_error(&thd->net);
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return 1;
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}
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return 0;
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}
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