MDEV-11485 Split Item_func_between::val_int() into virtual methods in Type_handler

- Removes "Item_result Item_func_opt_neg::m_compare_type" and introduces
  "Type_handler_hybrid_field_type Item_func_opt_neg::m_comparator" instead.

- Removes Item_func_between::compare_as_dates, because
  the new member m_comparator now contains the precise information
  about the data type that is used for comparison, which is important
  for TIME vs DATETIME.

- Adds a new method:
  Type_handler_hybrid_field_type::aggregate_for_comparison(const Type_handler*),
  as a better replacement for item_cmp_type(), which additionally can handle
  TIME vs DATE/DATETIME/TIMESTAMP correctly. Additionally, it correctly
  handles TIMESTAMP which fixes the problem reported in MDEV-11482.
  The old compare_as_dates/find_date_time_item() based code didn't handle
  comparison between TIME and TIMESTAMP correctly and erroneously used TIME
  comparison instead of DATETIME comparison.

- Adds a new method:
  Type_handler_hybrid_field_type::aggregate_for_comparison(Item **, uint nitems),
  as a better replacement for agg_cmp_type(), which can handle TIME.
- Splits Item_func_between::val_int() into pieces val_int_cmp_xxx(),
  one new method per XXX_RESULT.
- Adds a new virtual method Type_handler::Item_func_between_val_int()
  whose implementations use Item_func_between::val_int_cmp_xxx().
- Makes type_handler_longlong and type_handler_newdecimal public,
  as they are now needed in item_cmpfunc.cc.

Note:
This patch does not change Item_func_in to use the new aggregation methods,
so it still uses collect_cmp_type()/item_cmp_type() based aggregation.
Item_func_in will be changed in a separate patch and item_cmp_type() will be
removed.

sql/sql_type.h

@@ -29,6 +29,7 @@ class Item_cache;
 class Item_sum_hybrid;
 class Item_func_hex;
 class Item_func_hybrid_field_type;
+class Item_func_between;
 class Type_std_attributes;
 class Sort_param;
 class Arg_comparator;
@@ -314,6 +315,8 @@ public:
                                             MYSQL_TIME *,
                                             ulonglong fuzzydate) const= 0;
 
+  virtual longlong
+  Item_func_between_val_int(Item_func_between *func) const= 0;
 };
 
 
@@ -410,6 +413,7 @@ public:
     return true;
   }
 
+  longlong Item_func_between_val_int(Item_func_between *func) const;
 };
 
 
@@ -457,6 +461,7 @@ public:
   bool Item_func_hybrid_field_type_get_date(Item_func_hybrid_field_type *,
                                             MYSQL_TIME *,
                                             ulonglong fuzzydate) const;
+  longlong Item_func_between_val_int(Item_func_between *func) const;
 };
 
 
@@ -489,6 +494,7 @@ public:
   bool Item_func_hybrid_field_type_get_date(Item_func_hybrid_field_type *,
                                             MYSQL_TIME *,
                                             ulonglong fuzzydate) const;
+  longlong Item_func_between_val_int(Item_func_between *func) const;
 };
 
 
@@ -521,6 +527,7 @@ public:
   bool Item_func_hybrid_field_type_get_date(Item_func_hybrid_field_type *,
                                             MYSQL_TIME *,
                                             ulonglong fuzzydate) const;
+  longlong Item_func_between_val_int(Item_func_between *func) const;
 };
 
 
@@ -551,6 +558,7 @@ public:
   bool Item_func_hybrid_field_type_get_date(Item_func_hybrid_field_type *,
                                             MYSQL_TIME *,
                                             ulonglong fuzzydate) const;
+  longlong Item_func_between_val_int(Item_func_between *func) const;
 };
 
 
@@ -585,6 +593,7 @@ public:
   bool Item_func_hybrid_field_type_get_date(Item_func_hybrid_field_type *,
                                             MYSQL_TIME *,
                                             ulonglong fuzzydate) const;
+  longlong Item_func_between_val_int(Item_func_between *func) const;
 };
 
 
@@ -960,6 +969,10 @@ public:
   {
     return (m_type_handler= Type_handler::get_handler_by_result_type(type));
   }
+  const Type_handler *set_handler_by_cmp_type(Item_result type)
+  {
+    return (m_type_handler= Type_handler::get_handler_by_cmp_type(type));
+  }
   const Type_handler *set_handler_by_result_type(Item_result type,
                                                  uint max_octet_length,
                                                  CHARSET_INFO *cs)
@@ -977,6 +990,8 @@ public:
   {
     return (m_type_handler= Type_handler::get_handler_by_real_type(type));
   }
+  void aggregate_for_comparison(const Type_handler *other);
+  bool aggregate_for_comparison(Item **items, uint nitems);
 };
 
 
@@ -997,5 +1012,7 @@ public:
 extern Type_handler_row   type_handler_row;
 extern Type_handler_null  type_handler_null;
 extern Type_handler_varchar type_handler_varchar;
+extern Type_handler_longlong type_handler_longlong;
+extern Type_handler_newdecimal type_handler_newdecimal;
 
 #endif /* SQL_TYPE_H_INCLUDED */