code cleanup

fixed subselect error handling bug
fixed subselect UNION ALL bug
fixed thd->lex.select restoring
explain UNION subselect bug

mysql-test/r/subselect.result

@@ -204,4 +204,16 @@ date
 SELECT (SELECT DISTINCT date FROM searchconthardwarefr3 WHERE date='2002-08-03');
 (SELECT DISTINCT date FROM searchconthardwarefr3 WHERE date='2002-08-03')
 2002-08-03
+SELECT 1 FROM searchconthardwarefr3 WHERE 1=(SELECT 1 UNION SELECT 1) UNION ALL SELECT 1;
+1
+1
+1
+1
+SELECT 1 FROM searchconthardwarefr3 WHERE 1=(SELECT 1 UNION ALL SELECT 1) UNION SELECT 1;
+Subselect returns more than 1 record
+EXPLAIN SELECT 1 FROM searchconthardwarefr3 WHERE 1=(SELECT 1 UNION SELECT 1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	searchconthardwarefr3	index	NULL	topic	3	NULL	2	Using index
+2	SUBSELECT								No tables used
+3	UNION								No tables used
 drop table searchconthardwarefr3;

mysql-test/t/subselect.test

@@ -110,4 +110,8 @@ EXPLAIN SELECT DISTINCT date FROM searchconthardwarefr3 WHERE date='2002-08-03';
 EXPLAIN SELECT (SELECT DISTINCT date FROM searchconthardwarefr3 WHERE date='2002-08-03');
 SELECT DISTINCT date FROM searchconthardwarefr3 WHERE date='2002-08-03';
 SELECT (SELECT DISTINCT date FROM searchconthardwarefr3 WHERE date='2002-08-03');
+SELECT 1 FROM searchconthardwarefr3 WHERE 1=(SELECT 1 UNION SELECT 1) UNION ALL SELECT 1;
+-- error 1240
+SELECT 1 FROM searchconthardwarefr3 WHERE 1=(SELECT 1 UNION ALL SELECT 1) UNION SELECT 1;
+EXPLAIN SELECT 1 FROM searchconthardwarefr3 WHERE 1=(SELECT 1 UNION SELECT 1);
 drop table searchconthardwarefr3;
\ No newline at end of file

sql/sql_lex.cc

@@ -944,6 +944,7 @@ void st_select_lex_unit::init_query()
   global_parameters= this;
   select_limit_cnt= HA_POS_ERROR;
   offset_limit_cnt= 0;
+  union_option= 0;
   prepared= optimized= 0;
   item= 0;
 }

sql/sql_lex.h

@@ -240,6 +240,7 @@ class st_select_lex_unit: public st_select_lex_node {
   bool depended; /* depended from outer select subselect */
   /* not NULL if union used in subselect, point to subselect item */
   Item_subselect *item;
+  uint union_option;
 
   void init_query();
   bool create_total_list(THD *thd, st_lex *lex, TABLE_LIST **result);
@@ -373,7 +374,7 @@ typedef struct st_lex
   enum ha_rkey_function ha_rkey_mode;
   enum enum_enable_or_disable alter_keys_onoff;
   enum enum_var_type option_type;
-  uint grant, grant_tot_col, which_columns, union_option;
+  uint grant, grant_tot_col, which_columns;
   uint fk_delete_opt, fk_update_opt, fk_match_option;
   uint param_count;
   bool drop_primary, drop_if_exists, local_file, olap;

sql/sql_parse.cc

@@ -2904,7 +2904,6 @@ mysql_init_query(THD *thd)
   thd->select_number= thd->lex.select_lex.select_number= 1;
   thd->lex.value_list.empty();
   thd->free_list= 0;
-  thd->lex.union_option= 0;
   thd->lex.select= &thd->lex.select_lex;
   thd->lex.olap=thd->lex.describe=0;
   thd->lex.select->olap= UNSPECIFIED_OLAP_TYPE;

sql/sql_select.cc

@@ -371,7 +371,7 @@ JOIN::optimize()
 #endif
 
   conds=optimize_cond(conds,&cond_value);
-  if (thd->fatal_error)				// Out of memory
+  if (thd->fatal_error || thd->net.report_error)
   {
     delete procedure;
     error = 0;
@@ -7251,16 +7251,18 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
   select_result *result=join->result;
   Item *item_null= new Item_null();
   DBUG_ENTER("select_describe");
-
+  DBUG_PRINT("info", ("Select 0x%lx, type %s, message %s", 
+		      (ulong)join->select_lex, join->select_lex->type,
+		      message));
   /* Don't log this into the slow query log */
   select_lex->options&= ~(QUERY_NO_INDEX_USED | QUERY_NO_GOOD_INDEX_USED);
   join->unit->offset_limit_cnt= 0;
 
   if (message)
   {
-    item_list.push_back(new Item_int((int32) thd->lex.select->select_number));
-    item_list.push_back(new Item_string(thd->lex.select->type,
-					strlen(thd->lex.select->type),
+    item_list.push_back(new Item_int((int32) join->select_lex->select_number));
+    item_list.push_back(new Item_string(join->select_lex->type,
+					strlen(join->select_lex->type),
 					default_charset_info));
     Item *empty= new Item_empty_string("",0);
     for (uint i=0 ; i < 7; i++)
@@ -7285,9 +7287,10 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
       tmp2.length(0);
 
       item_list.empty();
-      item_list.push_back(new Item_int((int32) thd->lex.select->select_number));
-      item_list.push_back(new Item_string(thd->lex.select->type,
-					  strlen(thd->lex.select->type),
+      item_list.push_back(new Item_int((int32) 
+				       join->select_lex->select_number));
+      item_list.push_back(new Item_string(join->select_lex->type,
+					  strlen(join->select_lex->type),
 					  default_charset_info));
       if (tab->type == JT_ALL && tab->select && tab->select->quick)
 	tab->type= JT_RANGE;
@@ -7445,6 +7448,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
 
 int mysql_explain_union(THD *thd, SELECT_LEX_UNIT *unit, select_result *result)
 {
+  DBUG_ENTER("mysql_explain_union");
   int res= 0;
   SELECT_LEX *first= unit->first_select();
   for (SELECT_LEX *sl= first;
@@ -7467,12 +7471,14 @@ int mysql_explain_union(THD *thd, SELECT_LEX_UNIT *unit, select_result *result)
   }
   if (res > 0)
     res= -res; // mysql_explain_select do not report error
-  return res;
+  DBUG_RETURN(res);
 }
 
 int mysql_explain_select(THD *thd, SELECT_LEX *select_lex, char const *type, 
 			 select_result *result)
 {
+  DBUG_ENTER("mysql_explain_select");
+  DBUG_PRINT("info", ("Select 0x%lx, type %s", (ulong)select_lex, type))
   select_lex->type= type;
   thd->lex.select= select_lex;
   SELECT_LEX_UNIT *unit=  select_lex->master_unit();
@@ -7485,6 +7491,6 @@ int mysql_explain_select(THD *thd, SELECT_LEX *select_lex, char const *type,
 			(ORDER*) thd->lex.proc_list.first,
 			select_lex->options | thd->options | SELECT_DESCRIBE,
 			result, unit, select_lex, 0);
-  return res;
+  DBUG_RETURN(res);
 }
   

sql/sql_union.cc

@@ -110,7 +110,6 @@ int st_select_lex_unit::prepare(THD *thd, select_result *result)
     DBUG_RETURN(0);
   prepared= 1;
   union_result=0;
-  describe=(first_select()->options & SELECT_DESCRIBE) ? 1 : 0;
   res= 0;
   found_rows_for_union= false;
   TMP_TABLE_PARAM tmp_table_param;
@@ -122,30 +121,11 @@ int st_select_lex_unit::prepare(THD *thd, select_result *result)
   if (((void*)(global_parameters)) == ((void*)this))
   {
     found_rows_for_union= first_select()->options & OPTION_FOUND_ROWS && 
-      !describe && global_parameters->select_limit;
+      global_parameters->select_limit;
     if (found_rows_for_union)
       first_select()->options ^=  OPTION_FOUND_ROWS;
   }
   item_list.empty();
-  if (describe)
-  {
-    Item *item;
-    item_list.push_back(new Item_empty_string("table",NAME_LEN));
-    item_list.push_back(new Item_empty_string("type",10));
-    item_list.push_back(item=new Item_empty_string("possible_keys",
-						  NAME_LEN*MAX_KEY));
-    item->maybe_null=1;
-    item_list.push_back(item=new Item_empty_string("key",NAME_LEN));
-    item->maybe_null=1;
-    item_list.push_back(item=new Item_int("key_len",0,3));
-    item->maybe_null=1;
-    item_list.push_back(item=new Item_empty_string("ref",
-						    NAME_LEN*MAX_REF_PARTS));
-    item->maybe_null=1;
-    item_list.push_back(new Item_real("rows",0.0,0,10));
-    item_list.push_back(new Item_empty_string("Extra",255));
-  }
-  else
   {
     Item *item;
     List_iterator<Item> it(first_select()->item_list);
@@ -162,8 +142,7 @@ int st_select_lex_unit::prepare(THD *thd, select_result *result)
   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, !describe & 
-				!thd->lex.union_option,
+				(ORDER*) 0, !union_option,
 				1, 0,
 				(first_select()->options | thd->options |
 				 TMP_TABLE_ALL_COLUMNS),
@@ -179,7 +158,7 @@ int st_select_lex_unit::prepare(THD *thd, select_result *result)
   if (!(union_result=new select_union(table)))
     goto err;
 
-  union_result->save_time_stamp=!describe;
+  union_result->save_time_stamp=1;
   union_result->tmp_table_param=&tmp_table_param;
 
   // prepare selects
@@ -187,8 +166,7 @@ int st_select_lex_unit::prepare(THD *thd, select_result *result)
   for (sl= first_select(); sl; sl= sl->next_select())
   {
     JOIN *join= new JOIN(thd, sl->item_list, 
-			 sl->options | thd->options | SELECT_NO_UNLOCK | 
-			 ((describe) ? SELECT_DESCRIBE : 0),
+			 sl->options | thd->options | SELECT_NO_UNLOCK,
 			 union_result);
     joins.push_back(new JOIN_P(join));
     thd->lex.select=sl;
@@ -220,11 +198,12 @@ int st_select_lex_unit::prepare(THD *thd, select_result *result)
 int st_select_lex_unit::exec()
 {
   DBUG_ENTER("st_select_lex_unit::exec");
+  SELECT_LEX *lex_select_save= thd->lex.select;
+
   if(depended || !item || !item->assigned())
   {
     if (optimized && item && item->assigned())
       item->assigned(0); // We will reinit & rexecute unit
-    SELECT_LEX *lex_select_save= thd->lex.select;
     for (SELECT_LEX *sl= first_select(); sl; sl= sl->next_select())
     {
       thd->lex.select=sl;
@@ -236,27 +215,28 @@ int st_select_lex_unit::exec()
 	sl->options&= ~OPTION_FOUND_ROWS;
 
       if (!optimized)
-	sl->join->optimize();
+	res= sl->join->optimize();
       else
-	sl->join->reinit();
-
-      sl->join->exec();
-      res= sl->join->error;
+	res= sl->join->reinit();
 
+      if (!res)
+      {
+	sl->join->exec();
+	res= sl->join->error;
+      }
       if (res)
       {
 	thd->lex.select= lex_select_save;
 	DBUG_RETURN(res);
       }
     }
-    thd->lex.select= lex_select_save;
     optimized= 1;
   }
 
   if (union_result->flush())
   {
-    res= 1;					// Error is already sent
-    DBUG_RETURN(res);
+    thd->lex.select= lex_select_save;
+    DBUG_RETURN(1);
   }
 
   /* Send result to 'result' */
@@ -289,12 +269,8 @@ int st_select_lex_unit::exec()
 	select_limit_cnt= HA_POS_ERROR;		// no limit
       if (select_limit_cnt == HA_POS_ERROR)
 	thd->options&= ~OPTION_FOUND_ROWS;
-      if (describe)
-	select_limit_cnt= HA_POS_ERROR;		// no limit
       res= mysql_select(thd,&result_table_list,
 			item_list, NULL,
-			(describe) ? 
-			0: 
 			(ORDER*)global_parameters->order_list.first,
 			(ORDER*) NULL, NULL, (ORDER*) NULL,
 			thd->options, result, this, first_select(), 1);
@@ -303,6 +279,7 @@ int st_select_lex_unit::exec()
     }
   }
   thd->lex.select_lex.ftfunc_list= &thd->lex.select_lex.ftfunc_list_alloc;
+  thd->lex.select= lex_select_save;
   DBUG_RETURN(res);
 }
 

sql/sql_yacc.yy

@@ -4150,7 +4150,7 @@ optional_order_or_limit:
 
 union_option:
 	/* empty */ {}
-	| ALL {Lex->union_option=1;};
+	| ALL {Select->master_unit()->union_option= 1;};
 
 singleval_subselect:
 	subselect_start singleval_subselect_init