Fix for BUG#13410 - qualified reference to a view column in the HAVING clause cannot be resolved.

The problem was then when a column reference was resolved to a view column, the new Item
created for this column contained the name of the view, and not the view alias.


mysql-test/r/view.result:
  Additional test for BUG#13410.
mysql-test/t/view.test:
  Additional test for BUG#13410.
sql/item.cc:
  Correctly cast 'cur_field' to Item_ident because if the original item is
  an Item_field, the cur_field is either an Item_field or an Item_ref.
  Thus we have to cast cur_field to a common super-class of both.
sql/item.h:
  - real_item() may be called before Item_ref::ref is set
    (i.e. the Item_ref object was resolved).
  - To avoid a crash and to return some meaningful value
    in such cases we return 'this'.
sql/sql_base.cc:
  - 'item' may be an Item_ref, so we test for the type of the actual
    referenced item.
  - Correctly cast 'cur_field' to Item_ident because if the original
    item is an Item_field, the cur_field is either an Item_field or an
    Item_ref. Thus we have to cast cur_field to a common super-class
    of both.
sql/table.cc:
  - When creating a new Item for a reference to a view column, use the view alias,
    and not the real view name.
  - Removed old code

mysql-test/r/view.result

@@ -2286,5 +2286,15 @@ SELECT v1.a FROM v1 GROUP BY v1.a HAVING v1.a > 1;
 a
 2
 3
+SELECT t_1.a FROM t1 AS t_1 GROUP BY t_1.a HAVING t_1.a IN (1,2,3);
+a
+1
+2
+3
+SELECT v_1.a FROM v1 AS v_1 GROUP BY v_1.a HAVING v_1.a IN (1,2,3);
+a
+1
+2
+3
 DROP VIEW v1;
 DROP TABLE t1;

mysql-test/t/view.test

@@ -2162,6 +2162,8 @@ INSERT INTO t1 VALUES (1,1),(2,2),(3,3);
 CREATE VIEW v1 AS SELECT a,b FROM t1;
 SELECT t1.a FROM t1 GROUP BY t1.a HAVING t1.a > 1;
 SELECT v1.a FROM v1 GROUP BY v1.a HAVING v1.a > 1;
+SELECT t_1.a FROM t1 AS t_1 GROUP BY t_1.a HAVING t_1.a IN (1,2,3);
+SELECT v_1.a FROM v1 AS v_1 GROUP BY v_1.a HAVING v_1.a IN (1,2,3);
 
 DROP VIEW v1;
 DROP TABLE t1;

sql/item.cc

@@ -2973,7 +2973,7 @@ static Item** find_field_in_group_list(Item *find_item, ORDER *group_list)
   const char *field_name;
   ORDER      *found_group= NULL;
   int         found_match_degree= 0;
-  Item_field *cur_field;
+  Item_ident *cur_field;
   int         cur_match_degree= 0;
 
   if (find_item->type() == Item::FIELD_ITEM ||
@@ -2992,7 +2992,7 @@ static Item** find_field_in_group_list(Item *find_item, ORDER *group_list)
   {
     if ((*(cur_group->item))->real_item()->type() == Item::FIELD_ITEM)
     {
-      cur_field= (Item_field*) *cur_group->item;
+      cur_field= (Item_ident*) *cur_group->item;
       cur_match_degree= 0;
       
       DBUG_ASSERT(cur_field->field_name != 0);

sql/item.h

@@ -1619,7 +1619,7 @@ public:
   }
   Item *real_item()
   {
-    return (*ref)->real_item();
+    return (ref && *ref) ? (*ref)->real_item() : this;
   }
   bool walk(Item_processor processor, byte *arg)
   { return (*ref)->walk(processor, arg); }

sql/sql_base.cc

@@ -3357,9 +3357,9 @@ find_item_in_list(Item *find, List<Item> &items, uint *counter,
 
   for (uint i= 0; (item=li++); i++)
   {
-    if (field_name && item->type() == Item::FIELD_ITEM)
+    if (field_name && item->real_item()->type() == Item::FIELD_ITEM)
     {
-      Item_field *item_field= (Item_field*) item;
+      Item_ident *item_field= (Item_ident*) item;
 
       /*
 	In case of group_concat() with ORDER BY condition in the QUERY

sql/table.cc

@@ -2424,22 +2424,6 @@ Field *Natural_join_column::field()
 const char *Natural_join_column::table_name()
 {
   return table_ref->alias;
-  /*
-    TODO:
-    I think that it is sufficient to return just
-    table->alias, which is correctly set to either
-    the view name, the table name, or the alias to
-    the table reference (view or stored table).
-  */
-#ifdef NOT_YET
-  if (view_field)
-    return table_ref->view_name.str;
-
-  DBUG_ASSERT(!strcmp(table_ref->table_name,
-                      table_ref->table->s->table_name));
-  return table_ref->table_name;
-}
-#endif
 }
 
 
@@ -2575,7 +2559,7 @@ Item *create_view_field(THD *thd, TABLE_LIST *view, Item **field_ref,
     DBUG_RETURN(field);
   }
   Item *item= new Item_direct_view_ref(&view->view->select_lex.context,
-                                       field_ref, view->view_name.str,
+                                       field_ref, view->alias,
                                        name);
   DBUG_RETURN(item);
 }