Setting handler to have the return type as that of the element by which we are...

Setting handler to have the return type as that of the element by which we are ordering the partition

sql/item.h

@@ -5386,7 +5386,7 @@ class Cached_item_decimal :public Cached_item_item
   Cached_item_decimal(Item *item_par);
   bool cmp(void);
   int  cmp_read_only();
-  my_decimal get_value(){ return value;};
+  my_decimal *get_value(){ return &value;};
   void clear()
   {
     null_value= false;

sql/item_windowfunc.cc

@@ -210,6 +210,11 @@ void Item_sum_percentile_disc::setup_window_func(THD *thd, Window_spec *window_s
   setup_percentile_func(thd, window_spec->order_list);
 }
 
+void Item_sum_percentile_disc::set_type_handler(Window_spec *window_spec)
+{
+  type_handler()->get_handler_by_cmp_type(window_spec->order_list->first->item[0]->result_type());
+}
+
 bool Item_sum_dense_rank::add()
 {
   if (peer_tracker->check_if_next_group() || first_add)

sql/item_windowfunc.h

@@ -701,11 +701,13 @@ class Item_sum_ntile : public Item_sum_window_with_row_count
   ulong current_row_count_;
 };
 
-class Item_sum_percentile_disc : public Item_sum_cume_dist
+class Item_sum_percentile_disc : public Item_sum_cume_dist,
+                                 public Type_handler_hybrid_field_type
 {
 public:
   Item_sum_percentile_disc(THD *thd, Item* arg) : Item_sum_cume_dist(thd, arg),
-                              value(NULL), val_calculated(FALSE) {}
+                           Type_handler_hybrid_field_type(&type_handler_longlong),
+                           value(NULL), val_calculated(FALSE) {}
 
   double val_real()
   {
@@ -715,7 +717,7 @@ class Item_sum_percentile_disc : public Item_sum_cume_dist
       return 0;
     }
     null_value= false;
-    return ((Cached_item_int*) value)->get_value();
+    return ((Cached_item_real*) value)->get_value();
   }
 
   longlong val_int()
@@ -769,7 +771,9 @@ class Item_sum_percentile_disc : public Item_sum_cume_dist
   }
 
   void update_field() {}
-  const Type_handler *type_handler() const { return &type_handler_double; }
+  void set_type_handler(Window_spec *window_spec);
+  const Type_handler *type_handler() const
+  {return Type_handler_hybrid_field_type::type_handler();}
 
   void fix_length_and_dec()
   {

sql/sql_window.cc

@@ -319,6 +319,10 @@ setup_windows(THD *thd, Ref_ptr_array ref_pointer_array, TABLE_LIST *tables,
   while ((win_func_item= li++))
   {
     win_func_item->update_used_tables();
+    if (win_func_item->only_single_element_order_list())
+    {
+      ((Item_sum_percentile_disc*)win_func_item)->set_type_handler(win_func_item->window_spec);
+    }
   }
 
   DBUG_RETURN(0);