diff options
Diffstat (limited to 'sql/sql_derived.cc')
| -rw-r--r-- | sql/sql_derived.cc | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/sql/sql_derived.cc b/sql/sql_derived.cc new file mode 100644 index 00000000000..81eade6edb7 --- /dev/null +++ b/sql/sql_derived.cc @@ -0,0 +1,129 @@ +/* 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, + bool tables_is_opened) +{ + /* + 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 (TABLE_LIST *cursor= (TABLE_LIST *)tables; + cursor; + cursor=cursor->next) + { + if (cursor->derived) + { + res=mysql_derived(thd, lex, (SELECT_LEX_UNIT *)cursor->derived, + cursor, 0); + if (res) DBUG_RETURN(res); + } + } + Item *item; + List_iterator<Item> it(sl->item_list); + + while ((item= it++)) + item_list.push_back(item); + + if (tables_is_opened || !(res=open_and_lock_tables(thd,tables))) + { + if (tables && 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))) + { + 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; + + 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); + 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; + sl->exclude(); + t->derived=(SELECT_LEX *)0; // just in case ... + } + } + delete derived_result; + } + if (res) + free_tmp_table(thd,table); +exit: + close_thread_tables(thd); + if (res > 0) + send_error(thd, ER_UNKNOWN_COM_ERROR); // temporary only ... + } + DBUG_RETURN(res); +} |