Fix for a multi table updates when one of the tables is not updated

but used in a nested query.

mysql-test/r/multi_update.result

@@ -324,6 +324,7 @@ a	b
 7	7
 8	8
 9	9
+update t1,t2 set t1.b=t2.b, t1.a=t2.a where t1.a=t2.a and not exists (select * from t2 where t2.a > 10);
 drop table t1,t2;
 CREATE TABLE t3 (  KEY1 varchar(50) NOT NULL default '',  PARAM_CORR_DISTANCE_RUSH double default NULL,  PARAM_CORR_DISTANCE_GEM double default NULL,  PARAM_AVG_TARE double default NULL,  PARAM_AVG_NB_DAYS double default NULL,  PARAM_DEFAULT_PROP_GEM_SRVC varchar(50) default NULL,  PARAM_DEFAULT_PROP_GEM_NO_ETIK varchar(50) default NULL,  PARAM_SCENARIO_COSTS varchar(50) default NULL,  PARAM_DEFAULT_WAGON_COST double default NULL,  tmp int(11) default NULL,  PRIMARY KEY  (KEY1)) ENGINE=MyISAM;
 INSERT INTO t3 VALUES ('A',1,1,22,3.2,'R','R','BASE2',0.24,NULL);

mysql-test/t/multi_update.test

@@ -260,6 +260,10 @@ update t1,t2 set t1.b=t1.b+2,t2.b=t1.b+10 where t1.b between 3 and 5 and t2.a=t1
 select * from t1;
 select * from t2;
 
+# test for non-updating table which is also used in sub-select
+
+update t1,t2 set t1.b=t2.b, t1.a=t2.a where t1.a=t2.a and not exists (select * from t2 where t2.a > 10);
+
 drop table t1,t2;
 CREATE TABLE t3 (  KEY1 varchar(50) NOT NULL default '',  PARAM_CORR_DISTANCE_RUSH double default NULL,  PARAM_CORR_DISTANCE_GEM double default NULL,  PARAM_AVG_TARE double default NULL,  PARAM_AVG_NB_DAYS double default NULL,  PARAM_DEFAULT_PROP_GEM_SRVC varchar(50) default NULL,  PARAM_DEFAULT_PROP_GEM_NO_ETIK varchar(50) default NULL,  PARAM_SCENARIO_COSTS varchar(50) default NULL,  PARAM_DEFAULT_WAGON_COST double default NULL,  tmp int(11) default NULL,  PRIMARY KEY  (KEY1)) ENGINE=MyISAM;
 INSERT INTO t3 VALUES ('A',1,1,22,3.2,'R','R','BASE2',0.24,NULL);

sql/sql_update.cc

@@ -578,7 +578,7 @@ multi_update::multi_update(THD *thd_arg, TABLE_LIST *table_list,
 int multi_update::prepare(List<Item> &not_used_values,
 			  SELECT_LEX_UNIT *lex_unit)
 {
-  TABLE_LIST *table_ref;
+  TABLE_LIST *table_ref, *tables;
   SQL_LIST update;
   table_map tables_to_update= 0;
   Item_field *item;
@@ -604,8 +604,9 @@ int multi_update::prepare(List<Item> &not_used_values,
     We have to check values after setup_tables to get used_keys right in
     reference tables
   */
+  tables= thd->lex->select_lex.get_table_list();
 
-  if (setup_fields(thd, 0, all_tables, *values, 1, 0, 0))
+  if (setup_fields(thd, 0, tables, *values, 1, 0, 0))
     DBUG_RETURN(1);
 
   /*
@@ -615,7 +616,7 @@ int multi_update::prepare(List<Item> &not_used_values,
   */
 
   update.empty();
-  for (table_ref= all_tables;  table_ref; table_ref=table_ref->next)
+  for (table_ref= tables;  table_ref; table_ref=table_ref->next)
   {
     TABLE *table=table_ref->table;
     if (tables_to_update & table->map)
@@ -684,10 +685,10 @@ int multi_update::prepare(List<Item> &not_used_values,
     which will cause an error when reading a row.
     (This issue is mostly relevent for MyISAM tables)
   */
-  for (table_ref= all_tables;  table_ref; table_ref=table_ref->next)
+  for (table_ref= tables;  table_ref; table_ref=table_ref->next)
   {
     TABLE *table=table_ref->table;
-    if (!(tables_to_update & table->map) && 
+    if (!(tables_to_update & table->map) || !table->no_keyread && 
 	find_real_table_in_list(update_tables, table_ref->db,
 				table_ref->real_name))
       table->no_cache= 1;			// Disable row cache