From b95a23b1615997871d314a1926814d882fea712e Mon Sep 17 00:00:00 2001
From: Roland Bock <rbock@eudoxos.de>
Date: Sat, 17 Aug 2024 12:35:06 +0200
Subject: [PATCH] More tests and cleaner detection for result clause

(that is the clause that determines the result type of the statement)
---
 include/sqlpp11/core/clause/insert.h          |  5 +-
 include/sqlpp11/core/clause/remove.h          |  5 +-
 .../sqlpp11/core/clause/select_column_list.h  | 21 +++++++-
 include/sqlpp11/core/clause/union.h           |  4 +-
 include/sqlpp11/core/clause/update.h          |  5 +-
 include/sqlpp11/core/detail/get_last.h        | 13 ++---
 include/sqlpp11/core/group_by_column.h        |  5 ++
 include/sqlpp11/core/operator/as_expression.h | 15 ++++++
 include/sqlpp11/core/query/custom_query.h     |  3 +-
 include/sqlpp11/core/query/statement.h        |  8 +--
 include/sqlpp11/core/type_traits.h            |  4 +-
 include/sqlpp11/core/type_traits/aggregates.h |  6 +++
 include/sqlpp11/sqlite3/insert_or.h           |  5 +-
 tests/core/types/CMakeLists.txt               |  1 +
 tests/core/types/clause/select_columns.cpp    | 21 ++++++++
 tests/core/types/detail/CMakeLists.txt        | 32 +++++++++++
 tests/core/types/detail/get_last_if.cpp       | 54 +++++++++++++++++++
 17 files changed, 187 insertions(+), 20 deletions(-)
 create mode 100644 tests/core/types/detail/CMakeLists.txt
 create mode 100644 tests/core/types/detail/get_last_if.cpp

diff --git a/include/sqlpp11/core/clause/insert.h b/include/sqlpp11/core/clause/insert.h
index 87866118..b51db566 100644
--- a/include/sqlpp11/core/clause/insert.h
+++ b/include/sqlpp11/core/clause/insert.h
@@ -43,7 +43,7 @@ namespace sqlpp
 
   struct insert_t : public statement_name_t<insert_name_t>
   {
-    using _traits = make_traits<no_value_t, tag::is_return_value>;
+    using _traits = make_traits<no_value_t>;
     struct _sqlpp_name_tag
     {
     };
@@ -86,6 +86,9 @@ namespace sqlpp
     };
   };
 
+  template<>
+    struct is_result_clause<insert_t> : public std::true_type {};
+
   template <typename Context>
   auto to_sql_string(Context& , const insert_name_t&) -> std::string
   {
diff --git a/include/sqlpp11/core/clause/remove.h b/include/sqlpp11/core/clause/remove.h
index ee786267..446b9a32 100644
--- a/include/sqlpp11/core/clause/remove.h
+++ b/include/sqlpp11/core/clause/remove.h
@@ -42,7 +42,7 @@ namespace sqlpp
   };
   struct remove_t : public statement_name_t<remove_name_t>
   {
-    using _traits = make_traits<no_value_t, tag::is_return_value>;
+    using _traits = make_traits<no_value_t>;
     struct _sqlpp_name_tag
     {
     };
@@ -85,6 +85,9 @@ namespace sqlpp
     };
   };
 
+  template<>
+    struct is_result_clause<remove_t> : public std::true_type {};
+
   template <typename Context>
   auto to_sql_string(Context& , const remove_name_t&) -> std::string
   {
diff --git a/include/sqlpp11/core/clause/select_column_list.h b/include/sqlpp11/core/clause/select_column_list.h
index ee7372db..2130cda5 100644
--- a/include/sqlpp11/core/clause/select_column_list.h
+++ b/include/sqlpp11/core/clause/select_column_list.h
@@ -67,7 +67,7 @@ namespace sqlpp
     template <typename... Columns>
     struct select_traits
     {
-      using _traits = make_traits<no_value_t, tag::is_select_column_list, tag::is_return_value>;
+      using _traits = make_traits<no_value_t, tag::is_select_column_list>;
     };
 
     template <typename Column>
@@ -75,7 +75,6 @@ namespace sqlpp
     {
       using _traits = make_traits<value_type_of_t<Column>,
                                   tag::is_select_column_list,
-                                  tag::is_return_value,
                                   tag::is_expression,
                                   tag::is_selectable>;
     };
@@ -227,6 +226,24 @@ namespace sqlpp
   {
   };
 
+  // If a GROUP BY clause defines known aggregate columns or the SELECT columns contain an aggregate function then ALL
+  // columns need to be aggregate.
+  template <typename KnownAggregateColumns, typename... Columns>
+  struct has_correct_aggregates<KnownAggregateColumns, select_column_list_t<Columns...>>
+      : public std::integral_constant<
+            bool,
+            (detail::type_vector_size<KnownAggregateColumns>::value == 0 and
+             logic::none_t<contains_aggregate_function<remove_dynamic_t<remove_as_t<Columns>>>::value...>::value) or
+                logic::all_t<is_aggregate_expression<KnownAggregateColumns,
+                                                     remove_dynamic_t<remove_as_t<Columns>>>::value...>::value>
+  {
+  };
+
+  template <typename... Columns>
+  struct is_result_clause<select_column_list_t<Columns...>> : public std::true_type
+  {
+  };
+
   template <typename... Columns>
   struct nodes_of<select_column_list_t<Columns...>>
   {
diff --git a/include/sqlpp11/core/clause/union.h b/include/sqlpp11/core/clause/union.h
index 807ba31d..9fe191cf 100644
--- a/include/sqlpp11/core/clause/union.h
+++ b/include/sqlpp11/core/clause/union.h
@@ -60,7 +60,7 @@ namespace sqlpp
   template <typename Flag, typename Lhs, typename Rhs>
   struct union_t
   {
-    using _traits = make_traits<no_value_t, tag::is_union, tag::is_return_value>;
+    using _traits = make_traits<no_value_t, tag::is_union>;
     using _nodes = detail::type_vector<Lhs, Rhs>;
 
     using _data_t = union_data_t<Flag, Lhs, Rhs>;
@@ -91,8 +91,6 @@ namespace sqlpp
                                                       typename Rhs::_consistency_check>;
     };
 
-    template <typename Statement>
-    using _result_methods_t = typename Lhs::template _result_methods_t<Statement>;
   };
 
   SQLPP_PORTABLE_STATIC_ASSERT(assert_union_args_are_statements_t, "arguments for union() must be statements");
diff --git a/include/sqlpp11/core/clause/update.h b/include/sqlpp11/core/clause/update.h
index 61d69e1a..f6841f46 100644
--- a/include/sqlpp11/core/clause/update.h
+++ b/include/sqlpp11/core/clause/update.h
@@ -43,7 +43,7 @@ namespace sqlpp
 
   struct update_t : public statement_name_t<update_name_t>
   {
-    using _traits = make_traits<no_value_t, tag::is_return_value>;
+    using _traits = make_traits<no_value_t>;
     struct _sqlpp_name_tag
     {
     };
@@ -86,6 +86,9 @@ namespace sqlpp
     };
   };
 
+  template<>
+    struct is_result_clause<update_t> : public std::true_type {};
+
   template <typename Context>
   auto to_sql_string(Context& , const update_name_t&) -> std::string
   {
diff --git a/include/sqlpp11/core/detail/get_last.h b/include/sqlpp11/core/detail/get_last.h
index d94c0e55..93584193 100644
--- a/include/sqlpp11/core/detail/get_last.h
+++ b/include/sqlpp11/core/detail/get_last.h
@@ -33,22 +33,23 @@ namespace sqlpp
   namespace detail
   {
     template <template <typename> class Predicate, typename Default, typename... T>
-    struct get_last_if_impl;
+    struct get_last_if;
 
     template <template <typename> class Predicate, typename Default>
-    struct get_last_if_impl<Predicate, Default>
+    struct get_last_if<Predicate, Default>
     {
       using type = Default;
     };
 
     template <template <typename> class Predicate, typename Default, typename T, typename... Rest>
-    struct get_last_if_impl<Predicate, Default, T, Rest...>
+    struct get_last_if<Predicate, Default, T, Rest...>
     {
-      using rest = typename get_last_if_impl<Predicate, Default, Rest...>::type;
-      using type = typename std::conditional<std::is_same<rest, Default>::value and Predicate<T>::value, T, rest>::type;
+      using type = typename get_last_if<Predicate,
+                                             typename std::conditional<Predicate<T>::value, T, Default>::type,
+                                             Rest...>::type;
     };
 
     template <template <typename> class Predicate, typename Default, typename... T>
-    using get_last_if = typename get_last_if_impl<Predicate, Default, T...>::type;
+    using get_last_if_t = typename get_last_if<Predicate, Default, T...>::type;
   }  // namespace detail
 }  // namespace sqlpp
diff --git a/include/sqlpp11/core/group_by_column.h b/include/sqlpp11/core/group_by_column.h
index efc48f53..b052d11e 100644
--- a/include/sqlpp11/core/group_by_column.h
+++ b/include/sqlpp11/core/group_by_column.h
@@ -48,6 +48,11 @@ namespace sqlpp
       Expr _expr;
     };
 
+  template <typename KnownAggregateColumns, typename Expr>
+  struct is_aggregate_expression<KnownAggregateColumns, group_by_column<Expr>> : public std::true_type
+  {
+  };
+
   template <typename Expr>
   struct is_group_by_column<group_by_column<Expr>> : public std::true_type
   {
diff --git a/include/sqlpp11/core/operator/as_expression.h b/include/sqlpp11/core/operator/as_expression.h
index 50bb5fcc..0bb2212e 100644
--- a/include/sqlpp11/core/operator/as_expression.h
+++ b/include/sqlpp11/core/operator/as_expression.h
@@ -53,6 +53,21 @@ namespace sqlpp
 
   // No value_type_of or name_tag_of defined for as_expression, to prevent its usage outside of select columns.
 
+  template <typename T>
+  struct remove_as
+  {
+    using type = T;
+  };
+
+  template <typename Expression, typename AliasProvider>
+  struct remove_as<as_expression<Expression, AliasProvider>>
+  {
+    using type = Expression;
+  };
+
+  template <typename T>
+  using remove_as_t = typename remove_as<T>::type;
+
   template <typename Expression, typename AliasProvider>
   struct nodes_of<as_expression<Expression, AliasProvider>>
   {
diff --git a/include/sqlpp11/core/query/custom_query.h b/include/sqlpp11/core/query/custom_query.h
index de49bd1a..a26d8cf7 100644
--- a/include/sqlpp11/core/query/custom_query.h
+++ b/include/sqlpp11/core/query/custom_query.h
@@ -54,7 +54,8 @@ namespace sqlpp
     struct custom_parts_t
     {
       using _custom_query_t = custom_query_t<Parts...>;
-      using _maybe_hidden_result_type_provider = detail::get_first_if<is_return_value_t, noop, Parts...>;
+#warning: This should be get_last_if, I think.
+      using _maybe_hidden_result_type_provider = detail::get_first_if<is_result_clause, noop, Parts...>;
       using _result_type_provider = typename unhide<_maybe_hidden_result_type_provider>::type;
       using _result_methods_t = typename _result_type_provider::template _result_methods_t<_result_type_provider>;
     };
diff --git a/include/sqlpp11/core/query/statement.h b/include/sqlpp11/core/query/statement.h
index 7725a5b6..4d647ebe 100644
--- a/include/sqlpp11/core/query/statement.h
+++ b/include/sqlpp11/core/query/statement.h
@@ -114,7 +114,7 @@ namespace sqlpp
       // The common table expressions not covered by the with.
       using _required_ctes = detail::make_difference_set_t<_all_required_ctes, _all_provided_ctes>;
 
-      using _result_type_provider = detail::get_last_if<is_return_value_t, noop, Policies...>;
+      using _result_type_provider = detail::get_last_if_t<is_result_clause, noop, Policies...>;
 
       struct _result_methods_t : public _result_type_provider::template _result_methods_t<_statement_t>
       {
@@ -203,8 +203,10 @@ namespace sqlpp
                     tag::is_statement,
                     tag_if<tag::is_select, logic::any_t<is_select_t<Policies>::value...>::value>,
                     tag_if<tag::is_expression, is_expression_t<_policies_t>::value>,
-                    tag_if<tag::is_selectable, is_expression_t<_policies_t>::value>,
-                    tag_if<tag::is_return_value, logic::none_t<is_noop_t<_result_type_provider>::value>::value>>;
+                    tag_if<tag::is_selectable, is_expression_t<_policies_t>::value>
+#warning: reactivate
+                    //,tag_if<tag::is_return_value, logic::none_t<is_noop_t<_result_type_provider>::value>::value>
+                      >;
     using _name_tag_of = name_tag_of<_result_type_provider>;
     using _nodes = detail::type_vector<_policies_t>;
     using _used_outer_tables = typename _policies_t::_all_provided_outer_tables;
diff --git a/include/sqlpp11/core/type_traits.h b/include/sqlpp11/core/type_traits.h
index b3abcec6..779aaf37 100644
--- a/include/sqlpp11/core/type_traits.h
+++ b/include/sqlpp11/core/type_traits.h
@@ -222,7 +222,6 @@ namespace sqlpp
   SQLPP_VALUE_TRAIT_GENERATOR(is_cte)
   SQLPP_VALUE_TRAIT_GENERATOR(is_noop)
   SQLPP_VALUE_TRAIT_GENERATOR(is_missing)
-  SQLPP_VALUE_TRAIT_GENERATOR(is_return_value)
   SQLPP_VALUE_TRAIT_GENERATOR(is_raw_table)
   SQLPP_VALUE_TRAIT_GENERATOR(is_pre_join)
   SQLPP_VALUE_TRAIT_GENERATOR(is_join)
@@ -590,4 +589,7 @@ namespace sqlpp
 
   template <typename Db>
   using serializer_context_of = typename serializer_context_of_impl<Db>::type;
+
+  template<typename T>
+    struct is_result_clause : public std::false_type {};
 }  // namespace sqlpp
diff --git a/include/sqlpp11/core/type_traits/aggregates.h b/include/sqlpp11/core/type_traits/aggregates.h
index f0340d43..a50aad2d 100644
--- a/include/sqlpp11/core/type_traits/aggregates.h
+++ b/include/sqlpp11/core/type_traits/aggregates.h
@@ -80,5 +80,11 @@ namespace sqlpp
   {
   };
 
+  // If a GROUP BY clause defines known aggregate columns or the SELECT columns contain an aggregate function then ALL
+  // columns need to be aggregate.
+  // SELECT-like clauses will need to specialize this.
+  template <typename KnownAggregateColumns, typename T>
+  struct has_correct_aggregates : public std::true_type {};
+
 }  // namespace sqlpp11
 
diff --git a/include/sqlpp11/sqlite3/insert_or.h b/include/sqlpp11/sqlite3/insert_or.h
index 34a934e8..e632ae48 100644
--- a/include/sqlpp11/sqlite3/insert_or.h
+++ b/include/sqlpp11/sqlite3/insert_or.h
@@ -49,7 +49,7 @@ namespace sqlpp
     template <typename InsertOrAlternative>
     struct insert_or_t : public statement_name_t<InsertOrAlternative>
     {
-      using _traits = make_traits<no_value_t, tag::is_return_value>;
+      using _traits = make_traits<no_value_t>;
       struct _sqlpp_name_tag
       {
       };
@@ -78,6 +78,9 @@ namespace sqlpp
       };
     };
 
+  template<>
+    struct is_result_clause<insert_or_t> : public std::true_type {};
+
     template <typename InsertOrAlternative>
     using blank_insert_or_t =
         statement_t<insert_or_t<InsertOrAlternative>, no_into_t, no_insert_value_list_t>;
diff --git a/tests/core/types/CMakeLists.txt b/tests/core/types/CMakeLists.txt
index 442511eb..5a0b6677 100644
--- a/tests/core/types/CMakeLists.txt
+++ b/tests/core/types/CMakeLists.txt
@@ -38,4 +38,5 @@ test_compile(value)
 add_subdirectory(aggregate_function)
 add_subdirectory(operator)
 add_subdirectory(clause)
+add_subdirectory(detail)
 add_subdirectory(type_traits)
diff --git a/tests/core/types/clause/select_columns.cpp b/tests/core/types/clause/select_columns.cpp
index 16b55cd0..42084dfc 100644
--- a/tests/core/types/clause/select_columns.cpp
+++ b/tests/core/types/clause/select_columns.cpp
@@ -46,12 +46,21 @@ void test_select_columns()
 {
   auto v = sqlpp::value("text");
   auto col_int = test::TabFoo{}.id;
+  auto col_txt = test::TabFoo{}.textNnD;
+
+  using unknown = sqlpp::detail::type_vector<>;
+  using knownInt = sqlpp::detail::type_vector<decltype(col_int)>;
+  using knownTxt = sqlpp::detail::type_vector<decltype(col_txt)>;
 
   // Single column
   {
     using T = clause_of_t<decltype(select_columns(col_int))>;
     static_assert(std::is_same<sqlpp::name_tag_of_t<T>, test::TabFoo_::Id::_sqlpp_name_tag>::value, "");
     static_assert(std::is_same<sqlpp::value_type_of_t<T>, sqlpp::integral>::value, "");
+    static_assert(sqlpp::is_result_clause<T>::value, "");
+    static_assert(sqlpp::has_correct_aggregates<unknown, T>::value, "");
+    static_assert(sqlpp::has_correct_aggregates<knownInt, T>::value, "");
+    static_assert(not sqlpp::has_correct_aggregates<knownTxt, T>::value, "");
   }
 
   // Single dynamic column
@@ -59,6 +68,10 @@ void test_select_columns()
     using T = clause_of_t<decltype(select_columns(dynamic(true, col_int)))>;
     static_assert(std::is_same<sqlpp::name_tag_of_t<T>, test::TabFoo_::Id::_sqlpp_name_tag>::value, "");
     static_assert(std::is_same<sqlpp::value_type_of_t<T>, sqlpp::optional<sqlpp::integral>>::value, "");
+    static_assert(sqlpp::is_result_clause<T>::value, "");
+    static_assert(sqlpp::has_correct_aggregates<unknown, T>::value, "");
+    static_assert(sqlpp::has_correct_aggregates<knownInt, T>::value, "");
+    static_assert(not sqlpp::has_correct_aggregates<knownTxt, T>::value, "");
   }
 
   // Single declared group by column
@@ -66,6 +79,10 @@ void test_select_columns()
     using T = clause_of_t<decltype(select_columns(declare_group_by_column(v).as(cheese)))>;
     static_assert(std::is_same<sqlpp::name_tag_of_t<T>, cheese_t::_sqlpp_name_tag>::value, "");
     static_assert(std::is_same<sqlpp::value_type_of_t<T>, sqlpp::text>::value, "");
+    static_assert(sqlpp::is_result_clause<T>::value, "");
+    static_assert(sqlpp::has_correct_aggregates<unknown, T>::value, "");
+    static_assert(sqlpp::has_correct_aggregates<knownInt, T>::value, "");
+    static_assert(sqlpp::has_correct_aggregates<knownTxt, T>::value, "");
   }
 
   // Single dynamic declared group by column
@@ -73,6 +90,10 @@ void test_select_columns()
     using T = clause_of_t<decltype(select_columns(dynamic(true, declare_group_by_column(v)).as(cheese)))>;
     static_assert(std::is_same<sqlpp::name_tag_of_t<T>, cheese_t::_sqlpp_name_tag>::value, "");
     static_assert(std::is_same<sqlpp::value_type_of_t<T>, sqlpp::optional<sqlpp::text>>::value, "");
+    static_assert(sqlpp::is_result_clause<T>::value, "");
+    static_assert(sqlpp::has_correct_aggregates<unknown, T>::value, "");
+    static_assert(sqlpp::has_correct_aggregates<knownInt, T>::value, "");
+    static_assert(sqlpp::has_correct_aggregates<knownTxt, T>::value, "");
   }
 
 #warning: add actual tests here
diff --git a/tests/core/types/detail/CMakeLists.txt b/tests/core/types/detail/CMakeLists.txt
new file mode 100644
index 00000000..e3997826
--- /dev/null
+++ b/tests/core/types/detail/CMakeLists.txt
@@ -0,0 +1,32 @@
+# Copyright (c) 2024, Roland Bock
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without modification,
+# are permitted provided that the following conditions are met:
+#
+#   Redistributions of source code must retain the above copyright notice, this
+#   list of conditions and the following disclaimer.
+#
+#   Redistributions in binary form must reproduce the above copyright notice, this
+#   list of conditions and the following disclaimer in the documentation and/or
+#   other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+# ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+function(test_compile name)
+    set(target sqlpp11_core_types_clause_${name})
+    add_executable(${target} ${name}.cpp)
+    target_link_libraries(${target} PRIVATE sqlpp11::sqlpp11 sqlpp11_testing)
+endfunction()
+
+test_compile(get_last_if)
+
diff --git a/tests/core/types/detail/get_last_if.cpp b/tests/core/types/detail/get_last_if.cpp
new file mode 100644
index 00000000..27d9c0a6
--- /dev/null
+++ b/tests/core/types/detail/get_last_if.cpp
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2024, Roland Bock
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ *  * Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "Sample.h"
+#include <sqlpp11/sqlpp11.h>
+
+void test_get_last_if()
+{
+  auto v = sqlpp::value("text");
+  auto col_int = test::TabFoo{}.id;
+
+  // Ending on a matching type
+  static_assert(std::is_same<sqlpp::detail::get_last_if_t<sqlpp::is_integral, sqlpp::noop>, sqlpp::noop>::value, "");
+  static_assert(std::is_same<sqlpp::detail::get_last_if_t<sqlpp::is_integral, sqlpp::noop, int>, int>::value, "");
+  static_assert(std::is_same<sqlpp::detail::get_last_if_t<sqlpp::is_integral, sqlpp::noop, int, float, long>, long>::value, "");
+  static_assert(std::is_same<sqlpp::detail::get_last_if_t<sqlpp::is_integral, sqlpp::noop, int, float, long, short>, short>::value, "");
+  static_assert(std::is_same<sqlpp::detail::get_last_if_t<sqlpp::is_integral, sqlpp::noop, int, float, long, short, size_t>, short>::value, "");
+  static_assert(std::is_same<sqlpp::detail::get_last_if_t<sqlpp::is_numeric, sqlpp::noop, int, float, long, short, size_t>, size_t>::value, "");
+
+  // Ending on a non-matching type
+  static_assert(std::is_same<sqlpp::detail::get_last_if_t<sqlpp::is_integral, sqlpp::noop, double>, sqlpp::noop>::value, "");
+  static_assert(std::is_same<sqlpp::detail::get_last_if_t<sqlpp::is_integral, sqlpp::noop, int, double>, int>::value, "");
+  static_assert(std::is_same<sqlpp::detail::get_last_if_t<sqlpp::is_integral, sqlpp::noop, int, float, double>, int>::value, "");
+  static_assert(std::is_same<sqlpp::detail::get_last_if_t<sqlpp::is_integral, sqlpp::noop, int, float, long, double>, long>::value, "");
+  static_assert(std::is_same<sqlpp::detail::get_last_if_t<sqlpp::is_integral, sqlpp::noop, int, float, long, short, double>, short>::value, "");
+}
+
+int main()
+{
+  void test_get_last_if();
+}
+