diff --git a/include/sqlpp11/vendor/select_column_list.h b/include/sqlpp11/vendor/select_column_list.h
index 9760da5d..2c3d6042 100644
--- a/include/sqlpp11/vendor/select_column_list.h
+++ b/include/sqlpp11/vendor/select_column_list.h
@@ -198,8 +198,13 @@ namespace sqlpp
 								static_assert(_is_dynamic::value, "add_column can only be called for dynamic_column");
 								static_assert(is_named_expression_t<NamedExpression>::value, "invalid named expression argument in add_column()");
 								static_assert(TableCheckRequired::value or Policies::template _no_unknown_tables<NamedExpression>::value, "named expression uses tables unknown to this statement in add_column()");
+								using column_names = ::sqlpp::detail::make_type_set_t<typename Columns::_name_t...>;
+								static_assert(not ::sqlpp::detail::is_element_of<typename NamedExpression::_name_t, column_names>::value, "a column of this name is present in the select already");
 
-								using ok = ::sqlpp::detail::all_t<sqlpp::detail::identity_t, _is_dynamic, is_named_expression_t<NamedExpression>>;
+								using ok = ::sqlpp::detail::all_t<sqlpp::detail::identity_t, 
+											_is_dynamic, 
+											is_named_expression_t<NamedExpression>
+												>;
 
 								_add_column_impl(namedExpression, ok()); // dispatch to prevent compile messages after the static_assert
 							}
diff --git a/tests/SelectTest.cpp b/tests/SelectTest.cpp
index c54c7c2d..c82f1dc2 100644
--- a/tests/SelectTest.cpp
+++ b/tests/SelectTest.cpp
@@ -70,8 +70,7 @@ int main()
 
 	auto s = dynamic_select(db).dynamic_columns(all_of(t)).dynamic_flags().dynamic_from(t).extra_tables(f,t).dynamic_where().dynamic_group_by(t.alpha).dynamic_order_by().dynamic_having(t.gamma).dynamic_limit().dynamic_offset();
 	s.add_flag(sqlpp::distinct);
-#warning: this should fail because t.beta has been selected already
-	s.add_column(t.beta);
+	s.add_column(f.omega);
 	s.add_from(f);
 	s.add_where(t.alpha > 7);
 	s.add_having(t.alpha > 7);