three bug fixes and major code cleanup

mysql-test/r/union.result

@@ -230,3 +230,7 @@ id_master	id	text1	text2
 1	3	NULL	bar3
 1	4	foo4	bar4
 drop table if exists t1,t2;
+(SELECT 1,3) UNION (SELECT 2,1) ORDER BY (SELECT 2);
+1	3
+1	3
+2	1

mysql-test/t/union.test

@@ -124,3 +124,4 @@ INSERT INTO t2 (id, id_master, text1, text2) VALUES("4", "1",
 SELECT 1 AS id_master, 1 AS id, NULL AS text1, 'ABCDE' AS text2 UNION SELECT id_master, t2.id, text1, text2 FROM t1 LEFT JOIN t2 ON t1.id = t2.id_master;
 SELECT 1 AS id_master, 1 AS id, 'ABCDE' AS text1, 'ABCDE' AS text2 UNION SELECT id_master, t2.id, text1, text2 FROM t1 LEFT JOIN t2 ON t1.id = t2.id_master;
 drop table if exists t1,t2;
+(SELECT 1,3) UNION (SELECT 2,1) ORDER BY (SELECT 2);

sql/item_subselect.cc

@@ -684,7 +684,7 @@ int subselect_single_select_engine::prepare()
 		    (ORDER*) select_lex->group_list.first,
 		    select_lex->having,
 		    (ORDER*) 0, select_lex, 
-		    select_lex->master_unit(), 0, 0))
+		    select_lex->master_unit(), 0))
     return 1;
   thd->lex.current_select= save_select;
   return 0;

sql/mysql_priv.h

@@ -405,8 +405,7 @@ int mysql_select(THD *thd, Item ***rref_pointer_array,
 		 COND *conds, uint og_num, ORDER *order, ORDER *group,
 		 Item *having, ORDER *proc_param, ulong select_type, 
 		 select_result *result, SELECT_LEX_UNIT *unit, 
-		 SELECT_LEX *select_lex, bool fake_select_lex,
-		 bool tables_and_fields_initied);
+		 SELECT_LEX *select_lex,  bool tables_and_fields_initied);
 void free_underlaid_joins(THD *thd, SELECT_LEX *select);
 void fix_tables_pointers(SELECT_LEX *select_lex);
 void fix_tables_pointers(SELECT_LEX_UNIT *select_lex);

sql/sql_derived.cc

@@ -172,7 +172,7 @@ int mysql_derived(THD *thd, LEX *lex, SELECT_LEX_UNIT *unit,
 			  (ORDER *) select_cursor->group_list.first,
 			  select_cursor->having, (ORDER*) NULL,
 			  select_cursor->options | thd->options  | SELECT_NO_UNLOCK,
-			  derived_result, unit, select_cursor, 0, 1);
+			  derived_result, unit, select_cursor, 1);
 
       if (!res)
       {

sql/sql_lex.h

@@ -311,6 +311,11 @@ class st_select_lex_unit: public st_select_lex_node {
   st_select_lex_unit* master_unit();
   st_select_lex* outer_select();
   st_select_lex* first_select() { return (st_select_lex*) slave; }
+  st_select_lex* first_select_in_union() 
+  { 
+    return (slave && slave->linkage == GLOBAL_OPTIONS_TYPE) ?
+      (st_select_lex*) slave->next : (st_select_lex*) slave;
+  }
   st_select_lex_unit* next_unit() { return (st_select_lex_unit*) next; }
   void exclude_level();
 
@@ -404,6 +409,13 @@ class st_select_lex: public st_select_lex_node
   }
   
   friend void mysql_init_query(THD *thd);
+  void make_empty_select(st_select_lex *last_select)
+  {
+    select_number=INT_MAX;
+    init_query();
+    init_select();
+    include_neighbour(last_select);
+  }
 };
 typedef class st_select_lex SELECT_LEX;
 

sql/sql_parse.cc

@@ -2433,7 +2433,7 @@ mysql_execute_command(THD *thd)
 			(ORDER *)NULL,
 			select_lex->options | thd->options |
 			SELECT_NO_JOIN_CACHE,
-			result, unit, select_lex, 0, 0);
+			result, unit, select_lex, 0);
       if (thd->net.report_error)
 	res= -1;
       delete result;

sql/sql_prepare.cc

@@ -567,7 +567,7 @@ static bool mysql_test_select_fields(PREP_STMT *stmt, TABLE_LIST *tables,
 
   if (join->prepare(&select_lex->ref_pointer_array, tables, 
 		    wild_num, conds, og_num, order, group, having, proc, 
-                    select_lex, unit, 0, 0))
+                    select_lex, unit, 0))
     DBUG_RETURN(1);
 
   /* 

sql/sql_select.cc

@@ -182,7 +182,7 @@ int handle_select(THD *thd, LEX *lex, select_result *result)
 		      select_lex->having,
 		      (ORDER*) lex->proc_list.first,
 		      select_lex->options | thd->options,
-		      result, &(lex->unit), &(lex->select_lex), 0, 0);
+		      result, &(lex->unit), &(lex->select_lex), 0);
   if (res && result)
     result->abort();
 
@@ -268,7 +268,7 @@ JOIN::prepare(Item ***rref_pointer_array,
 	      Item *having_init,
 	      ORDER *proc_param_init, SELECT_LEX *select,
 	      SELECT_LEX_UNIT *unit,
-	      bool fake_select_lex, bool tables_and_fields_initied)
+	      bool tables_and_fields_initied)
 {
   DBUG_ENTER("JOIN::prepare");
 
@@ -279,7 +279,6 @@ JOIN::prepare(Item ***rref_pointer_array,
   proc_param= proc_param_init;
   tables_list= tables_init;
   select_lex= select;
-  if (!fake_select_lex)
   select_lex->join= this;
   union_part= (unit->first_select()->next_select() != 0);
 
@@ -1261,7 +1260,6 @@ int
 JOIN::cleanup(THD *thd)
 {
   DBUG_ENTER("JOIN::cleanup");
-
   select_lex->join= 0;
 
   if (tmp_join)
@@ -1292,15 +1290,14 @@ mysql_select(THD *thd, Item ***rref_pointer_array,
 	     COND *conds, uint og_num,  ORDER *order, ORDER *group,
 	     Item *having, ORDER *proc_param, ulong select_options,
 	     select_result *result, SELECT_LEX_UNIT *unit,
-	     SELECT_LEX *select_lex, bool fake_select_lex,
-	     bool tables_and_fields_initied)
+	     SELECT_LEX *select_lex,  bool tables_and_fields_initied)
 {
   int err;
   bool free_join= 1;
   DBUG_ENTER("mysql_select");
 
   JOIN *join;
-  if (!fake_select_lex && select_lex->join != 0)
+  if (select_lex->join != 0)
   {
     //here is EXPLAIN of subselect or derived table
     join= select_lex->join;
@@ -1320,8 +1317,7 @@ mysql_select(THD *thd, Item ***rref_pointer_array,
 
     if (join->prepare(rref_pointer_array, tables, wild_num,
 		      conds, og_num, order, group, having, proc_param,
-		      select_lex, unit, fake_select_lex,
-		      tables_and_fields_initied))
+		      select_lex, unit, tables_and_fields_initied))
     {
       DBUG_RETURN(-1);
     }
@@ -1350,7 +1346,7 @@ mysql_select(THD *thd, Item ***rref_pointer_array,
     thd->limit_found_rows= curr_join->send_records;
     thd->examined_row_count= curr_join->examined_rows;
     thd->proc_info="end";
-    err= (fake_select_lex ? curr_join->error : join->cleanup(thd));
+    err= join->cleanup(thd);
     if (thd->net.report_error)
       err= -1;
     delete join;
@@ -7086,15 +7082,16 @@ find_order_in_list(THD *thd, Item **ref_pointer_array,
 		   TABLE_LIST *tables,ORDER *order, List<Item> &fields,
 		   List<Item> &all_fields)
 {
-  if ((*order->item)->type() == Item::INT_ITEM)
+  Item *itemptr=*order->item;
+  if (itemptr->type() == Item::INT_ITEM)
   {						/* Order by position */
     Item *item=0;
 
-    uint count= (uint) ((Item_int*) (*order->item))->value;
+    uint count= (uint) ((Item_int*)itemptr)->value;
     if (count > fields.elements)
     {
       my_printf_error(ER_BAD_FIELD_ERROR,ER(ER_BAD_FIELD_ERROR),
-		      MYF(0),(*order->item)->full_name(),
+		      MYF(0),itemptr->full_name(),
 	       thd->where);
       return 1;
     }
@@ -7103,8 +7100,7 @@ find_order_in_list(THD *thd, Item **ref_pointer_array,
     return 0;
   }
   uint counter;
-  Item **item= find_item_in_list(*order->item, fields, &counter,
-				 IGNORE_ERRORS);
+  Item **item= find_item_in_list(itemptr, fields, &counter, IGNORE_ERRORS);
   if (item)
   {
     order->item= ref_pointer_array + counter;
@@ -8103,7 +8099,7 @@ int mysql_explain_select(THD *thd, SELECT_LEX *select_lex, char const *type,
 			select_lex->having,
 			(ORDER*) thd->lex.proc_list.first,
 			select_lex->options | thd->options | SELECT_DESCRIBE,
-			result, unit, select_lex, 0, 0);
+			result, unit, select_lex, 0);
   DBUG_RETURN(res);
 }
 

sql/sql_select.h

@@ -256,8 +256,7 @@ class JOIN :public Sql_alloc
   int prepare(Item ***rref_pointer_array, TABLE_LIST *tables, uint wind_num,
 	      COND *conds, uint og_num, ORDER *order, ORDER *group,
 	      Item *having, ORDER *proc_param, SELECT_LEX *select,
-	      SELECT_LEX_UNIT *unit, bool fake_select_lex,
-	      bool tables_and_fields_initied);
+	      SELECT_LEX_UNIT *unit, bool tables_and_fields_initied);
   int optimize();
   int reinit();
   void exec();

sql/sql_union.cc

@@ -122,9 +122,9 @@ int st_select_lex_unit::prepare(THD *thd, select_result *result,
   this->result= result;
   t_and_f= tables_and_fields_initied;
   SELECT_LEX_NODE *lex_select_save= thd->lex.current_select;
-  SELECT_LEX *sl;
+  SELECT_LEX *select_cursor;
 
-  thd->lex.current_select= sl= first_select();
+  thd->lex.current_select= select_cursor= first_select_in_union();
   /* Global option */
   if (((void*)(global_parameters)) == ((void*)this))
   {
@@ -136,26 +136,27 @@ int st_select_lex_unit::prepare(THD *thd, select_result *result,
   if (t_and_f)
   {
     // Item list and tables will be initialized by mysql_derived
-    item_list= sl->item_list;
+    item_list= select_cursor->item_list;
   }
   else
   {
     item_list.empty();
-    TABLE_LIST *first_table= (TABLE_LIST*) first_select()->table_list.first;
+    TABLE_LIST *first_table= (TABLE_LIST*) select_cursor->table_list.first;
 
     if (setup_tables(first_table) ||
-	setup_wild(thd, first_table, sl->item_list, 0, sl->with_wild))
+	setup_wild(thd, first_table, select_cursor->item_list, 0, select_cursor->with_wild))
       goto err;
-    List_iterator<Item> it(sl->item_list);	
+    List_iterator<Item> it(select_cursor->item_list);	
     Item *item;
     while((item=it++))
       item->maybe_null=1;
-    item_list= sl->item_list;
-    sl->with_wild= 0;
-    if (setup_ref_array(thd, &sl->ref_pointer_array, 
-			(item_list.elements + sl->with_sum_func +
-			 sl->order_list.elements + sl->group_list.elements)) ||
-	setup_fields(thd, sl->ref_pointer_array, first_table, item_list,
+    item_list= select_cursor->item_list;
+    select_cursor->with_wild= 0;
+    if (setup_ref_array(thd, &select_cursor->ref_pointer_array, 
+			(item_list.elements + select_cursor->with_sum_func +
+			 select_cursor->order_list.elements + 
+			 select_cursor->group_list.elements)) ||
+	setup_fields(thd, select_cursor->ref_pointer_array, first_table, item_list,
 		     0, 0, 1))
       goto err;
     t_and_f= 1;
@@ -165,7 +166,7 @@ int st_select_lex_unit::prepare(THD *thd, select_result *result,
   tmp_table_param.field_count=item_list.elements;
   if (!(table= create_tmp_table(thd, &tmp_table_param, item_list,
 				(ORDER*) 0, !union_option,
-				1, (first_select()->options | thd->options |
+				1, (select_cursor->options | thd->options |
 				    TMP_TABLE_ALL_COLUMNS),
 				HA_POS_ERROR)))
     goto err;
@@ -181,9 +182,16 @@ int st_select_lex_unit::prepare(THD *thd, select_result *result,
 
   union_result->not_describe=1;
   union_result->tmp_table_param=&tmp_table_param;
+
+/* 
+   the following piece of code is placed here solely for the purpose of 
+   getting correct results with EXPLAIN when UNION is withing a sub-select
+   or derived table ...
+*/  
+
   if (thd->lex.describe)
   {
-    for (SELECT_LEX *sl= first_select(); sl; sl= sl->next_select())
+    for (SELECT_LEX *sl= select_cursor; sl; sl= sl->next_select())
     {
       JOIN *join= new JOIN(thd, sl->item_list, 
 			   sl->options | thd->options | SELECT_NO_UNLOCK,
@@ -206,16 +214,17 @@ int st_select_lex_unit::prepare(THD *thd, select_result *result,
 			 (ORDER*) sl->group_list.first,
 			 sl->having,
 			 (ORDER*) NULL,
-			 sl, this, 0, t_and_f);
+			 sl, this, t_and_f);
       t_and_f= 0;
       if (res | thd->is_fatal_error)
 	goto err;
     }
   }
+
   item_list.empty();
   thd->lex.current_select= lex_select_save;
   {
-    List_iterator<Item> it(first_select()->item_list);
+    List_iterator<Item> it(select_cursor->item_list);
     Field **field;
 
     for (field= table->field; *field; field++)
@@ -236,6 +245,7 @@ int st_select_lex_unit::exec()
 {
   DBUG_ENTER("st_select_lex_unit::exec");
   SELECT_LEX_NODE *lex_select_save= thd->lex.current_select;
+  SELECT_LEX *select_cursor=first_select_in_union(), *last_select;
 
   if (executed && !(dependent || uncacheable))
     DBUG_RETURN(0);
@@ -249,8 +259,9 @@ int st_select_lex_unit::exec()
       item->reset();
       table->file->delete_all_rows();
     }
-    for (SELECT_LEX *sl= first_select(); sl; sl= sl->next_select())
+    for (SELECT_LEX *sl= select_cursor; sl; sl= sl->next_select())
     {
+      last_select=sl;
       if (optimized)
 	res= sl->join->reinit();
       else
@@ -276,7 +287,7 @@ int st_select_lex_unit::exec()
 			   (ORDER*) sl->group_list.first,
 			   sl->having,
 			   (ORDER*) NULL,
-			   sl, this, 0, t_and_f);
+			   sl, this, t_and_f);
 	t_and_f=0;
 	if (res | thd->is_fatal_error)
 	{
@@ -307,7 +318,7 @@ int st_select_lex_unit::exec()
   /* Send result to 'result' */
 
   // to correct ORDER BY reference resolving
-  thd->lex.current_select = first_select();
+  thd->lex.current_select = select_cursor;
   res =-1;
   {
 #if 0
@@ -321,9 +332,10 @@ int st_select_lex_unit::exec()
 
     if (!thd->is_fatal_error)			// Check if EOM
     {
-      SELECT_LEX *sl=thd->lex.current_select->master_unit()->first_select();
-      offset_limit_cnt= (sl->braces) ? global_parameters->offset_limit : 0;
-      select_limit_cnt= (sl->braces) ? global_parameters->select_limit+
+      SELECT_LEX *fake_select  = new SELECT_LEX();
+      fake_select->make_empty_select(last_select);
+      offset_limit_cnt= (select_cursor->braces) ? global_parameters->offset_limit : 0;
+      select_limit_cnt= (select_cursor->braces) ? global_parameters->select_limit+
 	global_parameters->offset_limit : HA_POS_ERROR;
       if (select_limit_cnt < global_parameters->select_limit)
 	select_limit_cnt= HA_POS_ERROR;		// no limit
@@ -334,9 +346,11 @@ int st_select_lex_unit::exec()
 			global_parameters->order_list.elements,
 			(ORDER*)global_parameters->order_list.first,
 			(ORDER*) NULL, NULL, (ORDER*) NULL,
-			thd->options, result, this, first_select(), 1, 0);
+			thd->options, result, this, fake_select, 0);
       if (found_rows_for_union && !res)
 	thd->limit_found_rows = (ulonglong)table->file->records;
+      fake_select->exclude();
+      delete fake_select;
     }
   }
   thd->lex.select_lex.ftfunc_list= &thd->lex.select_lex.ftfunc_list_alloc;
@@ -357,7 +371,7 @@ int st_select_lex_unit::cleanup()
       free_tmp_table(thd, table);
     table= 0; // Safety
   }
-  for (SELECT_LEX *sl= first_select(); sl; sl= sl->next_select())
+  for (SELECT_LEX *sl= first_select_in_union(); sl; sl= sl->next_select())
   {
     JOIN *join;
     if ((join= sl->join))

sql/sql_update.cc

@@ -428,7 +428,7 @@ int mysql_multi_update(THD *thd,
 		    conds, 0, (ORDER *) NULL, (ORDER *)NULL, (Item *) NULL,
 		    (ORDER *)NULL,
 		    options | SELECT_NO_JOIN_CACHE,
-		    result, unit, select_lex, 0, 0);
+		    result, unit, select_lex, 0);
   delete result;
   DBUG_RETURN(res);
 }