Fix for BUG#12941: in create_tmp_field(), if the passed item is an Item_ref, put newly

created item into item->result_field, not *(item->ref)->result_field.

mysql-test/r/view.result

@@ -2151,3 +2151,29 @@ select * from v1;
 strcmp(f1,'a')
 drop view v1;
 drop table t1;
+create table t1 (
+r_object_id char(16) NOT NULL,
+group_name varchar(32) NOT NULL
+) engine = InnoDB;
+create table t2 (
+r_object_id char(16) NOT NULL,
+i_position int(11) NOT NULL, 
+users_names varchar(32) default NULL
+) Engine = InnoDB;
+create view v1 as select r_object_id, group_name from t1;
+create view v2 as select r_object_id, i_position, users_names from t2;
+create unique index r_object_id on t1(r_object_id);
+create index group_name on t1(group_name);
+create unique index r_object_id_i_position on t2(r_object_id,i_position);
+create index users_names on t2(users_names);
+insert into t1 values('120001a080000542','tstgroup1');
+insert into t2 values('120001a080000542',-1, 'guser01');
+insert into t2 values('120001a080000542',-2, 'guser02');
+select v1.r_object_id, v2.users_names from v1, v2
+where (v1.group_name='tstgroup1') and v2.r_object_id=v1.r_object_id 
+order by users_names;
+r_object_id	users_names
+120001a080000542	guser01
+120001a080000542	guser02
+drop view v1, v2;
+drop table t1, t2;

mysql-test/t/view.test

@@ -2018,3 +2018,36 @@ create view v1 as select strcmp(f1,'a') from t1;
 select * from v1;
 drop view v1;
 drop table t1;
+
+#
+# BUG#12941
+#
+create table t1 (
+  r_object_id char(16) NOT NULL,
+  group_name varchar(32) NOT NULL
+) engine = InnoDB;
+
+create table t2 (
+  r_object_id char(16) NOT NULL,
+  i_position int(11) NOT NULL, 
+  users_names varchar(32) default NULL
+) Engine = InnoDB;
+
+create view v1 as select r_object_id, group_name from t1;
+create view v2 as select r_object_id, i_position, users_names from t2;
+
+create unique index r_object_id on t1(r_object_id);
+create index group_name on t1(group_name);
+create unique index r_object_id_i_position on t2(r_object_id,i_position);
+create index users_names on t2(users_names);
+
+insert into t1 values('120001a080000542','tstgroup1');
+insert into t2 values('120001a080000542',-1, 'guser01');
+insert into t2 values('120001a080000542',-2, 'guser02');
+
+select v1.r_object_id, v2.users_names from v1, v2
+where (v1.group_name='tstgroup1') and v2.r_object_id=v1.r_object_id 
+order by users_names;
+
+drop view v1, v2;
+drop table t1, t2;

sql/sql_select.cc

@@ -8054,12 +8054,17 @@ Field *create_tmp_field(THD *thd, TABLE *table,Item *item, Item::Type type,
                         bool table_cant_handle_bit_fields,
                         uint convert_blob_length)
 {
+  Item::Type orig_type;
+  Item *orig_item;
+
   if (type != Item::FIELD_ITEM &&
       item->real_item()->type() == Item::FIELD_ITEM &&
       (item->type() != Item::REF_ITEM ||
        !((Item_ref *) item)->depended_from))
   {
+    orig_item= item;
     item= item->real_item();
+    orig_type= type;
     type= Item::FIELD_ITEM;
   }
   switch (type) {
@@ -8075,29 +8080,34 @@ Field *create_tmp_field(THD *thd, TABLE *table,Item *item, Item::Type type,
   case Item::DEFAULT_VALUE_ITEM:
   {
     Item_field *field= (Item_field*) item;
+    bool orig_modify= modify_item;
+    Field *result;
+    if (orig_type == Item::REF_ITEM)
+      modify_item= 0;
     /*
       If item have to be able to store NULLs but underlaid field can't do it,
       create_tmp_field_from_field() can't be used for tmp field creation.
     */
     if (field->maybe_null && !field->field->maybe_null())
     {
-      Field *res= create_tmp_field_from_item(thd, item, table, NULL,
+      result= create_tmp_field_from_item(thd, item, table, NULL,
                                        modify_item, convert_blob_length);
       *from_field= field->field;
-      if (res && modify_item)
-        ((Item_field*)item)->result_field= res;
-      return res;
-    }
-
-    if (table_cant_handle_bit_fields && 
-        field->field->type() == FIELD_TYPE_BIT)
-      return create_tmp_field_from_item(thd, item, table, copy_func,
+      if (result && modify_item)
+        ((Item_field*)item)->result_field= result;
+    } 
+    else if (table_cant_handle_bit_fields && field->field->type() == FIELD_TYPE_BIT)
+      result= create_tmp_field_from_item(thd, item, table, copy_func,
                                         modify_item, convert_blob_length);
-    return create_tmp_field_from_field(thd, (*from_field= field->field),
+    else
+      result= create_tmp_field_from_field(thd, (*from_field= field->field),
                                        item->name, table,
                                        modify_item ? (Item_field*) item :
                                        NULL,
                                        convert_blob_length);
+    if (orig_type == Item::REF_ITEM && orig_modify)
+      ((Item_ref*)orig_item)->set_result_field(result);
+    return result;
   }
   /* Fall through */
   case Item::FUNC_ITEM: