diff --git a/include/sqlpp11/group_by.h b/include/sqlpp11/group_by.h
index 65e8d5ff..9d5a3965 100644
--- a/include/sqlpp11/group_by.h
+++ b/include/sqlpp11/group_by.h
@@ -192,7 +192,7 @@ namespace sqlpp
 					-> _new_statement_t<_check<Expressions...>, group_by_t<void, Expressions...>>
 					{
 						static_assert(sizeof...(Expressions), "at least one expression (e.g. a column) required in group_by()");
-						static_assert(detail::all_t<is_expression_t<Expressions>::value...>::value, "at least one argument is not an expression in group_by()");
+						static_assert(_check<Expressions...>::value, "at least one argument is not an expression in group_by()");
 
 						return _group_by_impl<void>(_check<Expressions...>{}, expressions...);
 					}
@@ -202,7 +202,7 @@ namespace sqlpp
 					-> _new_statement_t<_check<Expressions...>, group_by_t<_database_t, Expressions...>>
 					{
 						static_assert(not std::is_same<_database_t, void>::value, "dynamic_group_by must not be called in a static statement");
-						static_assert(detail::all_t<is_expression_t<Expressions>::value...>::value, "at least one argument is not an expression in group_by()");
+						static_assert(_check<Expressions...>::value, "at least one argument is not an expression in group_by()");
 
 						return _group_by_impl<_database_t>(_check<Expressions...>{}, expressions...);
 					}
diff --git a/include/sqlpp11/order_by.h b/include/sqlpp11/order_by.h
index cc893efb..aa7fc9ad 100644
--- a/include/sqlpp11/order_by.h
+++ b/include/sqlpp11/order_by.h
@@ -180,7 +180,7 @@ namespace sqlpp
 				using _database_t = typename Policies::_database_t;
 
 				template<typename... T>
-					using _check = detail::all_t<is_expression_t<T>::value...>;
+					using _check = detail::all_t<is_sort_order_t<T>::value...>;
 
 				template<typename Check, typename T>
 					using _new_statement_t = new_statement_t<Check::value, Policies, no_order_by_t, T>;
@@ -192,7 +192,7 @@ namespace sqlpp
 					-> _new_statement_t<_check<Expressions...>, order_by_t<void, Expressions...>>
 					{
 						static_assert(sizeof...(Expressions), "at least one expression (e.g. a column) required in order_by()");
-						static_assert(detail::all_t<is_expression_t<Expressions>::value...>::value, "at least one argument is not an expression in order_by()");
+						static_assert(_check<Expressions...>::value, "at least one argument is not a sort order in order_by()");
 
 						return _order_by_impl<void>(_check<Expressions...>{}, expressions...);
 					}
@@ -202,7 +202,7 @@ namespace sqlpp
 					-> _new_statement_t<_check<Expressions...>, order_by_t<_database_t, Expressions...>>
 					{
 						static_assert(not std::is_same<_database_t, void>::value, "dynamic_order_by must not be called in a static statement");
-						static_assert(detail::all_t<is_expression_t<Expressions>::value...>::value, "at least one argument is not an expression in order_by()");
+						static_assert(_check<Expressions...>::value, "at least one argument is not a sort order in order_by()");
 
 						return _order_by_impl<_database_t>(_check<Expressions...>{}, expressions...);
 					}