Second phase of UNIONS (please do not test it yet) and some other

changes. This is mostly a merge between my repository and central 
one, so that I can take a test for multi table delete and fix it.

sql/mysql_priv.h

@@ -232,6 +232,7 @@ bool mysql_rename_tables(THD *thd, TABLE_LIST *table_list);
 bool mysql_change_db(THD *thd,const char *name);
 void mysql_parse(THD *thd,char *inBuf,uint length);
 void mysql_init_select(LEX *lex);
+void mysql_new_select(LEX *lex);
 void init_max_user_conn(void);
 void free_max_user_conn(void);
 pthread_handler_decl(handle_one_connection,arg);
@@ -304,6 +305,7 @@ int mysql_select(THD *thd,TABLE_LIST *tables,List<Item> &list,COND *conds,
                  List<Item_func_match> &ftfuncs,
 		 ORDER *order, ORDER *group,Item *having,ORDER *proc_param,
 		 uint select_type,select_result *result);
+int mysql_union(THD *thd,LEX *lex, uint no);
 Field *create_tmp_field(TABLE *table,Item *item, Item::Type type,
 			Item_result_field ***copy_func, Field **from_field,
 			bool group,bool modify_item);

sql/sql_class.h

@@ -608,7 +608,7 @@ public:
    bool do_delete;
  public:
    multi_delete(TABLE_LIST *dt, thr_lock_type o, uint n)
-     : delete_tables (dt), lock_option(o), deleted(0), num_of_tables(n), error(0)
+     : delete_tables(dt), deleted(0), num_of_tables(n), error(0), lock_option(o)
    {
      thd = current_thd; do_delete = false;
    }

sql/sql_lex.h

@@ -55,7 +55,7 @@ enum enum_sql_command {
   SQLCOM_RESET, SQLCOM_PURGE, SQLCOM_SHOW_BINLOGS,
   SQLCOM_SHOW_OPEN_TABLES, SQLCOM_LOAD_MASTER_DATA,
   SQLCOM_HA_OPEN, SQLCOM_HA_CLOSE, SQLCOM_HA_READ,
-  SQLCOM_SHOW_SLAVE_HOSTS, SQLCOM_MULTI_DELETE
+  SQLCOM_SHOW_SLAVE_HOSTS, SQLCOM_MULTI_DELETE, SQLCOM_UNION_SELECT
 };
 
 enum lex_states { STATE_START, STATE_CHAR, STATE_IDENT,

sql/sql_parse.cc

@@ -47,6 +47,7 @@ static void mysql_init_query(THD *thd);
 static void remove_escape(char *name);
 static void refresh_status(void);
 static bool append_file_to_dir(char **filename_ptr, char *table_name);
+static inline int link_in_large_list_and_check_acl(THD *thd,LEX *lex,SQL_LIST *tables);
 
 const char *any_db="*any*";	// Special symbol for check_access
 
@@ -1719,6 +1720,30 @@ mysql_execute_command(void)
      close_thread_tables(thd);
      break;
    }
+  case SQLCOM_UNION_SELECT:
+  {
+    uint total_selects = select_lex->select_number; total_selects++;
+    SQL_LIST *total=(SQL_LIST *) thd->calloc(sizeof(SQL_LIST));
+    if (select_lex->options & SELECT_DESCRIBE)
+      lex->exchange=0;
+    res = link_in_large_list_and_check_acl(thd,lex,total);
+    if (res == -1)
+    {
+      res=0;
+      break;
+    }
+    if (res && (res=check_access(thd, lex->exchange ? SELECT_ACL | FILE_ACL : SELECT_ACL, any_db)))
+    {
+      res=0;
+      break;
+    }
+    if (!(res=open_and_lock_tables(thd,(TABLE_LIST *)total->first)))
+    {
+      res=mysql_union(thd,lex,total_selects);
+      if (res==-1) res=0;
+    }
+    break;
+  }
   case SQLCOM_DROP_TABLE:
     {
       if (check_table_access(thd,DROP_ACL,tables))
@@ -2405,6 +2430,14 @@ mysql_init_select(LEX *lex)
   select_lex->next = (SELECT_LEX *)NULL; 
 }
 
+void
+mysql_new_select(LEX *lex)
+{
+  uint select_no=lex->select->select_number;
+  SELECT_LEX *select_lex = (SELECT_LEX *)sql_calloc(sizeof(SELECT_LEX));
+  lex->select->next=select_lex; 
+  lex->select=select_lex; lex->select->select_number = ++select_no;
+}
 
 void
 mysql_parse(THD *thd,char *inBuf,uint length)
@@ -2838,6 +2871,40 @@ TABLE_LIST *add_table_to_list(Table_ident *table, LEX_STRING *alias,
   DBUG_RETURN(ptr);
 }
 
+static inline int link_in_large_list_and_check_acl(THD *thd,LEX *lex,SQL_LIST *tables)
+{
+  SELECT_LEX *sl; const char *current_db=thd->db ? thd->db : "";
+  for (sl=&lex->select_lex;sl;sl=sl->next)
+  {
+    if ((lex->sql_command == SQLCOM_UNION_SELECT) && (sl->order_list.first != (byte *)NULL) && (sl->next != (st_select_lex  *)NULL))
+    {
+      net_printf(&thd->net,ER_ILLEGAL_GRANT_FOR_TABLE);  // correct error message will come here; only last SELECt can have ORDER BY
+      return -1;
+    }
+    if (sl->table_list.first == (byte *)NULL) continue;
+    TABLE_LIST *cursor,*aux=(TABLE_LIST*) sl->table_list.first;
+    if (aux)
+    {
+      if (check_table_access(thd, lex->exchange ? SELECT_ACL | FILE_ACL : SELECT_ACL , aux))
+	return -1;
+      for (;aux;aux=aux->next)
+      {
+	if (!aux->db)
+	  aux->db=(char *)current_db;
+	for (cursor=(TABLE_LIST *)tables->first;cursor;cursor=cursor->next)
+	  if (!strcmp(cursor->db,aux->db) && (!strcmp(cursor->real_name,aux->real_name)))
+	    break;
+	if (!cursor ||  !tables->first)
+	{
+	  aux->lock_type= lex->lock_option;
+	  link_in_list(tables,(byte*)aux,(byte**) &aux->next);
+	}
+      }
+    }
+  }
+  return (tables->first) ? 0 : 1;
+}
+
 void add_join_on(TABLE_LIST *b,Item *expr)
 {
   if (!b->on_expr)

sql/sql_unions.cc

+/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & Monty & Sinisa
+   
+   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 */
+
+
+/* Union  of selects */
+
+#include "mysql_priv.h"
+
+/*
+  Do a union of selects
+*/
+
+
+int mysql_union(THD *thd,LEX *lex,uint no_of_selects) 
+{
+  SELECT_LEX *sl;
+  for (sl=&lex->select_lex;sl;sl=sl->next)
+  {
+  }
+}

sql/sql_yacc.yy

@@ -543,7 +543,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b,int *yystacksize);
 	opt_mi_check_type opt_to mi_check_types normal_join
 	table_to_table_list table_to_table opt_table_list opt_as
 	handler_rkey_function handler_rkey_mode handler_read_or_scan
-	single_multi table_multi_delete table_sini_wild
+	single_multi table_multi_delete table_sini_wild union union_list
 END_OF_INPUT
 
 %type <NONE>
@@ -1260,11 +1260,11 @@ select:
 	SELECT_SYM
 	{
 	  LEX *lex=Lex;
-	  lex->sql_command= SQLCOM_SELECT;
+	  if (lex->sql_command!=SQLCOM_UNION_SELECT)  lex->sql_command= SQLCOM_SELECT;
 	  lex->lock_option=TL_READ;
 	  mysql_init_select(lex);
 	}
-	select_options select_item_list select_into select_lock_type
+	select_options select_item_list select_into select_lock_type union
 
 select_into:
 	limit_clause {}
@@ -3155,3 +3155,23 @@ commit:
 
 rollback:
 	ROLLBACK_SYM { Lex->sql_command = SQLCOM_ROLLBACK;}
+
+
+/*
+** UNIONS : glue selects together
+*/
+
+
+union:	
+  /* empty */ {}
+  | union_list
+
+union_list:
+  UNION_SYM  
+  {
+    LEX *lex=Lex;
+    if (lex->exchange) YYABORT; /* Only the last SELECT can have  INTO...... */
+    lex->sql_command=SQLCOM_UNION_SELECT;
+    mysql_new_select(lex); lex->select->linkage=UNION_TYPE;
+  } 
+  select