UNION stuff mainly.

sql/sql_class.h:
  Made some temporary changes for UNION's. Still waiting for Monty's 
  comments on this.
sql/sql_delete.cc:
  Added a comment as Monty suggested
sql/sql_parse.cc:
  Some speedups for UNIONs
sql/sql_unions.cc:
  First attempts at running UNION's. 
  
  Removed header temporarily because of some bug in my pre-processor.

sql/sql_class.h

@@ -421,7 +421,7 @@ public:
   virtual int prepare(List<Item> &list) { return 0; }
   virtual bool send_fields(List<Item> &list,uint flag)=0;
   virtual bool send_data(List<Item> &items)=0;
-  virtual void initialize_tables (JOIN *join=0) {};
+  virtual void initialize_tables (JOIN *join=0) {}
   virtual void send_error(uint errcode,const char *err)=0;
   virtual bool send_eof()=0;
   virtual void abort() {}
@@ -475,14 +475,13 @@ public:
   bool send_eof();
 };
 class select_insert :public select_result {
- protected:
+ public:
   TABLE *table;
   List<Item> *fields;
   uint save_time_stamp;
   ulonglong last_insert_id;
   COPY_INFO info;
 
-public:
   select_insert(TABLE *table_par,List<Item> *fields_par,enum_duplicates duplic)
     :table(table_par),fields(fields_par), save_time_stamp(0),last_insert_id(0)
     {

sql/sql_delete.cc

@@ -17,6 +17,8 @@
 
 /* Delete of records */
 
+/* Multi-table deletes were introduced by Monty and Sinisa */
+
 #include "mysql_priv.h"
 #include "ha_innobase.h"
 #include "sql_select.h"

sql/sql_parse.cc

@@ -2445,13 +2445,13 @@ 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;
-  lex->select->item_list = lex->select_lex.item_list; 
-  lex->select->item_list.empty();
-  lex->select->table_list = lex->select_lex.table_list; 
-  lex->select->table_list.elements=0;
-  lex->select->table_list.first=0;
-  lex->select->table_list.next= (byte**) &lex->select->table_list.first;
+  lex->select=select_lex; select_lex->select_number = ++select_no;
+  select_lex->table_list.elements=0;
+  select_lex->table_list.first=0;
+  select_lex->table_list.next= (byte**) &select_lex->table_list.first;
+  select_lex->item_list.empty(); select_lex->when_list.empty(); 
+  select_lex->expr_list.empty();  select_lex->interval_list.empty(); 
+  select_lex->use_index.empty(); select_lex->ftfunc_list.empty();
 }
 
 void

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 */
+#include "mysql_priv.h"
 
 
 /* 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)
+  SELECT_LEX *sl, *for_order=&lex->select_lex; uint no=0; int res;
+  List<Item> fields;     TABLE *table;
+  for (;for_order->next;for_order=for_order->next);
+  ORDER *some_order = (ORDER *)for_order->order_list.first;
+  for (sl=&lex->select_lex;sl;sl=sl->next, no++)
+  {
+    TABLE_LIST *tables=(TABLE_LIST*) sl->table_list.first;
+    if (!no) // First we do CREATE from SELECT
+    {
+      select_create *result;
+      lex->create_info.options=HA_LEX_CREATE_TMP_TABLE;
+      if ((result=new select_create(tables->db ? tables->db : thd->db,
+				    NULL, &lex->create_info,
+				    lex->create_list,
+				    lex->key_list,
+				    sl->item_list,DUP_IGNORE)))
+      {
+	res=mysql_select(thd,tables,sl->item_list,
+			 sl->where,
+			 sl->ftfunc_list,
+			 (ORDER*) NULL,
+			 (ORDER*) sl->group_list.first,
+			 sl->having,
+			 (ORDER*) some_order,
+			 sl->options | thd->options,
+			 result);
+	if (res) 
+	{
+	  result->abort();
+	  delete result;
+	  return res;
+	}
+	else
+	{
+	  table=result->table;
+	  List_iterator<Item> it(*(result->fields));
+	  Item *item;
+	  while ((item= it++))
+	    fields.push_back(item);
+	}
+	delete result;
+	if (reopen_table(table)) return 1;
+      }
+      else
+	return -1;
+    }
+    else // Then we do INSERT from SELECT
+    {
+      select_result *result;
+      if ((result=new select_insert(table, &fields, DUP_IGNORE)))
+      {
+	res=mysql_select(thd,tables,sl->item_list,
+			 sl->where,
+                         sl->ftfunc_list,
+			 (ORDER*) some_order,
+			 (ORDER*) sl->group_list.first,
+			 sl->having,
+			 (ORDER*) NULL,
+			 sl->options | thd->options,
+			 result);
+	delete result;
+	if (res) return 1;
+      }
+      else
+	return -1;
+    }
+  }
+  if (1) // Meaning if not SELECT ... INTO .... which will be done later
+  {
+    READ_RECORD	info;
+    int error=0;
+    if (send_fields(thd,fields,1)) return 1;
+    SQL_SELECT	*select= new SQL_SELECT;
+    select->head=table;
+    select->file=*(table->io_cache);
+    init_read_record(&info,thd,table,select,1,1);
+    while (!(error=info.read_record(&info)) && !thd->killed)
+    {
+      
+      if (error)
+      {
+	table->file->print_error(error,MYF(0));
+	break;
+      }
+    }
+    end_read_record(&info);
+    delete select;
+  }
+  else
   {
   }
   return 0;