diff --git a/sql/my_decimal.h b/sql/my_decimal.h
index 775617dce0f..22800c24338 100644
--- a/sql/my_decimal.h
+++ b/sql/my_decimal.h
@@ -288,7 +288,7 @@ int my_decimal_set_zero(my_decimal *d)
 {
   /*
     We need the up-cast here, since my_decimal has sign() member functions,
-    which conflicts with decimal_t::size
+    which conflicts with decimal_t::sign
     (and decimal_make_zero is a macro, rather than a funcion).
   */
   decimal_make_zero(static_cast<decimal_t*>(d));