diff --git a/include/sqlpp11/core/basic/parameter.h b/include/sqlpp11/core/basic/parameter.h
index 00b45605..f81e9c69 100644
--- a/include/sqlpp11/core/basic/parameter.h
+++ b/include/sqlpp11/core/basic/parameter.h
@@ -33,12 +33,12 @@
 
 namespace sqlpp
 {
+#warning: It would be sufficient to store the NameTag here, not the whole NameTagProvider
   template <typename ValueType, typename NameType>
   struct parameter_t : public enable_comparison<parameter_t<ValueType, NameType>>
   {
     using _traits = make_traits<ValueType, tag::is_parameter, tag::is_expression>;
 
-    using _parameters = detail::type_vector<parameter_t>;
     using _is_literal_expression = std::true_type;
 
     using _instance_t = member_t<NameType, parameter_value_t<ValueType>>;
@@ -52,6 +52,12 @@ namespace sqlpp
     ~parameter_t() = default;
   };
 
+  template<typename ValueType, typename NameType>
+  struct parameters_of<parameter_t<ValueType, NameType>>
+  {
+    using type = detail::type_vector<parameter_t<ValueType, NameType>>;
+  };
+  
   template<typename ValueType, typename NameType>
   struct value_type_of<parameter_t<ValueType, NameType>>
   {
diff --git a/include/sqlpp11/core/clause/cte.h b/include/sqlpp11/core/clause/cte.h
index 07bc94fe..1aa8f711 100644
--- a/include/sqlpp11/core/clause/cte.h
+++ b/include/sqlpp11/core/clause/cte.h
@@ -40,8 +40,6 @@ namespace sqlpp
   template <typename Flag, typename Lhs, typename Rhs>
   struct cte_union_t
   {
-    using _parameters = detail::type_vector_cat_t<parameters_of<Lhs>, parameters_of<Rhs>>;
-
     cte_union_t(Lhs lhs, Rhs rhs) : _lhs(lhs), _rhs(rhs)
     {
     }
@@ -303,9 +301,6 @@ namespace sqlpp
     }
   };
 
-   template<typename NameTagProvider>
-    struct is_table<cte_ref_t<NameTagProvider>> : public std::true_type{};
-
    template<typename NameTagProvider>
     struct name_tag_of<cte_ref_t<NameTagProvider>> : public name_tag_of<NameTagProvider>
     {};
diff --git a/include/sqlpp11/core/clause/with.h b/include/sqlpp11/core/clause/with.h
index 2c2a43a3..41c202d7 100644
--- a/include/sqlpp11/core/clause/with.h
+++ b/include/sqlpp11/core/clause/with.h
@@ -62,7 +62,7 @@ namespace sqlpp
     using _nodes = detail::type_vector<>;
     using _provided_ctes =
         detail::make_joined_set_t<required_ctes_of<Expressions>...>;  // WITH provides common table expressions
-    using _parameters = detail::type_vector_cat_t<parameters_of<Expressions>...>;
+    using _parameters = detail::type_vector_cat_t<parameters_of_t<Expressions>...>;
 
     using _data_t = with_data_t<Expressions...>;
 
@@ -80,6 +80,7 @@ namespace sqlpp
       using _consistency_check = consistent_t;
     };
   };
+#warning: Need traits here! And type tests for them
 
   struct no_with_t
   {
diff --git a/include/sqlpp11/core/database/parameter_list.h b/include/sqlpp11/core/database/parameter_list.h
index fbfd16b1..78ddb22a 100644
--- a/include/sqlpp11/core/database/parameter_list.h
+++ b/include/sqlpp11/core/database/parameter_list.h
@@ -64,6 +64,7 @@ namespace sqlpp
     }
   };
 
+#warning: Why would we need this?
   template <typename Exp>
-  using make_parameter_list_t = parameter_list_t<parameters_of<Exp>>;
+  using make_parameter_list_t = parameter_list_t<parameters_of_t<Exp>>;
 }  // namespace sqlpp
diff --git a/include/sqlpp11/core/query/custom_query.h b/include/sqlpp11/core/query/custom_query.h
index 1303350d..6d89dd61 100644
--- a/include/sqlpp11/core/query/custom_query.h
+++ b/include/sqlpp11/core/query/custom_query.h
@@ -69,7 +69,7 @@ namespace sqlpp
     using _nodes = detail::type_vector<Parts...>;
 
     using _parameter_check =
-        typename std::conditional<parameters_of<custom_query_t>::empty(),
+        typename std::conditional<parameters_of_t<custom_query_t>::empty(),
                                   consistent_t,
                                   assert_no_parameters_t>::type;
     using _run_check = detail::get_first_if<is_inconsistent_t, consistent_t, _parameter_check>;
diff --git a/include/sqlpp11/core/query/statement.h b/include/sqlpp11/core/query/statement.h
index 91a72c90..cdb15043 100644
--- a/include/sqlpp11/core/query/statement.h
+++ b/include/sqlpp11/core/query/statement.h
@@ -123,7 +123,7 @@ namespace sqlpp
       //   - the select is complete (leaks no table requirements or cte requirements)
       static constexpr bool _can_be_used_as_table()
       {
-        return has_result_row<_statement_t>::value and _required_tables_of::empty() == 0 and
+        return has_result_row<_statement_t>::value and _required_tables_of::empty() and
                _required_ctes_of::empty();
       }
 
@@ -140,11 +140,11 @@ namespace sqlpp
                                         detail::make_intersect_set_t<required_tables_of_t<_result_type_provider>,
                                                                      _all_provided_optional_tables>::size::value != 0>;
                                         */
-      using _parameters = detail::type_vector_cat_t<parameters_of<Policies>...>;
+      using _parameters = detail::type_vector_cat_t<parameters_of_t<Policies>...>;
       // required_tables and _required_ctes are defined above
 
       using _cte_check =
-          typename std::conditional<_required_ctes_of::empty() == 0, consistent_t, assert_no_unknown_ctes_t>::type;
+          typename std::conditional<_required_ctes_of::empty(), consistent_t, assert_no_unknown_ctes_t>::type;
       using _table_check =
           typename std::conditional<_required_tables_of::empty(), consistent_t, assert_no_unknown_tables_t>::type;
       using _parameter_check = typename std::
diff --git a/include/sqlpp11/core/type_traits.h b/include/sqlpp11/core/type_traits.h
index 2a2bbc0a..ac397526 100644
--- a/include/sqlpp11/core/type_traits.h
+++ b/include/sqlpp11/core/type_traits.h
@@ -404,26 +404,20 @@ namespace sqlpp
   template <typename KnownAggregates, typename T>
   using is_non_aggregate_expression_t = typename detail::is_non_aggregate_expression_impl<KnownAggregates, T>::type;
 
-  namespace detail
+  template<typename T>
+  struct parameters_of
   {
-    template <typename T, typename Leaf = void>
-    struct parameters_of_impl
-    {
-      using type = typename parameters_of_impl<nodes_of_t<T>>::type;
-    };
-    template <typename T>
-    struct parameters_of_impl<T, typename std::enable_if<std::is_class<typename T::_parameters>::value>::type>
-    {
-      using type = typename T::_parameters;
-    };
-    template <typename... Nodes>
-    struct parameters_of_impl<type_vector<Nodes...>, void>
-    {
-      using type = detail::type_vector_cat_t<typename parameters_of_impl<Nodes>::type...>;
-    };
-  }  // namespace detail
+    using type = typename parameters_of<nodes_of_t<T>>::type;
+  };
+
+  template<typename... T>
+  struct parameters_of<detail::type_vector<T...>>
+  {
+    using type = detail::type_vector_cat_t<typename parameters_of<T>::type...>;
+  };
+
   template <typename T>
-  using parameters_of = typename detail::parameters_of_impl<T>::type;
+  using parameters_of_t = typename parameters_of<T>::type;
 
   // Something that can be used as a table
   template <typename T>
diff --git a/tests/core/types/clause/cte.cpp b/tests/core/types/clause/cte.cpp
index 8d73fc75..12ad97cd 100644
--- a/tests/core/types/clause/cte.cpp
+++ b/tests/core/types/clause/cte.cpp
@@ -31,21 +31,68 @@ void test_cte()
   const auto foo = test::TabFoo{};
   const auto bar = test::TabBar{};
 
-#warning: add more tests
+#warning: add more tests, including parameters and dynamic parts
+#warning: Can we union dynamically?
+
   // Simple CTE: X AS SELECT
   {
     auto x = cte(sqlpp::alias::x).as(select(foo.id).from(foo).unconditionally());
     auto a = x.as(sqlpp::alias::a);
 
     using X = decltype(x);
-    using R = decltype(make_table_ref(x));
+    using RX = decltype(make_table_ref(x));
     using A = decltype(a);
+    using RA = decltype(make_table_ref(a));
 
+    // CTE is used in WITH and in FROM
     static_assert(sqlpp::is_cte<X>::value, "");
     static_assert(not sqlpp::is_recursive_cte<X>::value, "");
     static_assert(sqlpp::is_table<X>::value, "");
     static_assert(sqlpp::required_ctes_of_t<X>::empty(), "");
-    static_assert(std::is_same<sqlpp::provided_ctes_of_t<X>, sqlpp::detail::type_vector<R>>::value, "");
+    static_assert(std::is_same<sqlpp::provided_ctes_of_t<X>, sqlpp::detail::type_vector<RX>>::value, "");
+
+    // CTE reference is what is stored in from_t or join_t.
+    // While it refers to a CTE, it cannot be used as a CTE or table, i.e. with(rx) or from(ra) would not compile.
+    static_assert(not sqlpp::is_cte<RX>::value, "");
+    static_assert(not sqlpp::is_table<RX>::value, "");
+
+    // CTEs can be aliased (e.g. x AS a). This alias can be used as a table in FROM, but not as a CTE in WITH.
+    static_assert(not sqlpp::is_cte<A>::value, "");
+    static_assert(sqlpp::is_table<A>::value, "");
+    static_assert(std::is_same<A, RA>::value, "");
+  }
+
+  // Simple CTE with parameter
+  {
+    auto p = sqlpp::parameter(foo.id);
+    auto x = cte(sqlpp::alias::x).as(select(foo.id).from(foo).where(foo.id > p));
+    auto a = x.as(sqlpp::alias::a);
+
+    using X = decltype(x);
+    using RX = decltype(make_table_ref(x));
+    using A = decltype(a);
+    using RA = decltype(make_table_ref(a));
+    using P = decltype(p);
+
+    // CTE is used in WITH and in FROM
+    static_assert(sqlpp::is_cte<X>::value, "");
+    static_assert(not sqlpp::is_recursive_cte<X>::value, "");
+    static_assert(sqlpp::is_table<X>::value, "");
+    static_assert(sqlpp::required_ctes_of_t<X>::empty(), "");
+    static_assert(std::is_same<sqlpp::provided_ctes_of_t<X>, sqlpp::detail::type_vector<RX>>::value, "");
+    static_assert(std::is_same<sqlpp::parameters_of_t<X>, sqlpp::detail::type_vector<P>>::value, "");
+
+    // CTE reference is what is stored in from_t or join_t.
+    // While it refers to a CTE, it cannot be used as a CTE or table, i.e. with(rx) or from(ra) would not compile.
+    static_assert(not sqlpp::is_cte<RX>::value, "");
+    static_assert(not sqlpp::is_table<RX>::value, "");
+    static_assert(sqlpp::parameters_of_t<RX>::empty(), "");
+
+    // CTEs can be aliased (e.g. x AS a). This alias can be used as a table in FROM, but not as a CTE in WITH.
+    static_assert(not sqlpp::is_cte<A>::value, "");
+    static_assert(sqlpp::is_table<A>::value, "");
+    static_assert(std::is_same<A, RA>::value, "");
+    static_assert(sqlpp::parameters_of_t<RA>::empty(), "");
   }
 
   // Non-recursive union CTE: X AS SELECT ... UNION ALL SELECT ...
diff --git a/tests/core/types/result_row.cpp b/tests/core/types/result_row.cpp
index 02d56d60..69a29738 100644
--- a/tests/core/types/result_row.cpp
+++ b/tests/core/types/result_row.cpp
@@ -304,6 +304,8 @@ int main()
   }
 }
 
+#warning: Test with CTEs
+
 int main(int, char* [])
 {
   single_table();