item_cmpfunc.cc, item.cc:

  Additional fix for bug #21475
item_func.h, item_func.cc:
  Additional fix for bug#16861

sql/item.cc

@@ -305,6 +305,7 @@ Item::Item():
   maybe_null=null_value=with_sum_func=unsigned_flag=0;
   decimals= 0; max_length= 0;
   with_subselect= 0;
+  cmp_context= (Item_result)-1;
 
   /* Put item in free list so that we can free all items at end */
   THD *thd= current_thd;
@@ -343,7 +344,8 @@ Item::Item(THD *thd, Item *item):
   unsigned_flag(item->unsigned_flag),
   with_sum_func(item->with_sum_func),
   fixed(item->fixed),
-  collation(item->collation)
+  collation(item->collation),
+  cmp_context(item->cmp_context)
 {
   next= thd->free_list;				// Put in free list
   thd->free_list= this;
@@ -3788,7 +3790,8 @@ Item *Item_field::equal_fields_propagator(byte *arg)
     The same problem occurs when comparing a DATE/TIME field with a
     DATE/TIME represented as an int and as a string.
   */
-  if (!item || item->cmp_context != cmp_context)
+  if (!item ||
+      (cmp_context != (Item_result)-1 && item->cmp_context != cmp_context))
     item= this;
   return item;
 }

sql/item_cmpfunc.cc

@@ -1220,6 +1220,7 @@ void Item_func_between::fix_length_and_dec()
   if (!args[0] || !args[1] || !args[2])
     return;
   agg_cmp_type(thd, &cmp_type, args, 3);
+  args[0]->cmp_context= args[1]->cmp_context= args[2]->cmp_context= cmp_type;
 
   if (cmp_type == STRING_RESULT)
       agg_arg_charsets(cmp_collation, args, 3, MY_COLL_CMP_CONV, 1);

sql/item_func.cc

@@ -3897,6 +3897,19 @@ bool Item_func_set_user_var::send(Protocol *protocol, String *str_arg)
   return Item::send(protocol, str_arg);
 }
 
+void Item_func_set_user_var::make_field(Send_field *tmp_field)
+{
+  if (result_field)
+  {
+    result_field->make_field(tmp_field);
+    DBUG_ASSERT(tmp_field->table_name != 0);
+    if (Item::name)
+      tmp_field->col_name=Item::name;               // Use user supplied name
+  }
+  else
+    Item::make_field(tmp_field);
+}
+
 String *
 Item_func_get_user_var::val_str(String *str)
 {

sql/item_func.h

@@ -1175,6 +1175,7 @@ class Item_func_set_user_var :public Item_func
   bool update_hash(void *ptr, uint length, enum Item_result type,
   		   CHARSET_INFO *cs, Derivation dv, bool unsigned_arg= 0);
   bool send(Protocol *protocol, String *str_arg);
+  void make_field(Send_field *tmp_field);
   bool check(bool use_result_field);
   bool update();
   enum Item_result result_type () const { return cached_result_type; }