diff --git a/sql/item_func.cc b/sql/item_func.cc
index cfb1106..b088f2a 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -3371,6 +3371,26 @@ my_decimal *Item_func_floor::decimal_op(my_decimal *decimal_value) {
   return nullptr;
 }

+enum_monotonicity_info Item_func_floor::get_monotonicity_info() const {
+  if (args[0]->type() == Item::FIELD_ITEM &&
+      (args[0]->data_type() == MYSQL_TYPE_DECIMAL ||
+       args[0]->data_type() == MYSQL_TYPE_TINY ||
+       args[0]->data_type() == MYSQL_TYPE_SHORT ||
+       args[0]->data_type() == MYSQL_TYPE_INT24 ||
+       args[0]->data_type() == MYSQL_TYPE_LONG ||
+       args[0]->data_type() == MYSQL_TYPE_FLOAT ||
+       args[0]->data_type() == MYSQL_TYPE_DOUBLE ||
+       args[0]->data_type() == MYSQL_TYPE_LONGLONG))
+    return MONOTONIC_INCREASING;
+
+  return args[0]->get_monotonicity_info();
+}
+
+longlong Item_func_floor::val_int_endpoint(bool, bool *) {
+  assert(fixed == 1);
+  return int_op();
+}
+
 bool Item_func_round::resolve_type(THD *thd) {
   if (param_type_is_default(thd, 0, 1, MYSQL_TYPE_NEWDECIMAL)) return true;
   if (param_type_is_default(thd, 1, 2, MYSQL_TYPE_LONGLONG)) return true;
diff --git a/sql/item_func.h b/sql/item_func.h
index e89ca49..190543a 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -1387,6 +1387,8 @@ class Item_func_floor final : public Item_func_int_val {
   longlong int_op() override;
   double real_op() override;
   my_decimal *decimal_op(my_decimal *) override;
+  enum_monotonicity_info get_monotonicity_info() const override;
+  longlong val_int_endpoint(bool left_endp, bool *incl_endp) override;
   bool check_partition_func_processor(uchar *) override { return false; }
   bool check_function_as_value_generator(uchar *) override { return false; }
   enum Functype functype() const override { return FLOOR_FUNC; }