diff --git a/include/sqlpp11/core/clause/select_column_list.h b/include/sqlpp11/core/clause/select_column_list.h
index 1bd61feb..32b8f5ec 100644
--- a/include/sqlpp11/core/clause/select_column_list.h
+++ b/include/sqlpp11/core/clause/select_column_list.h
@@ -215,6 +215,7 @@ namespace sqlpp
       }
     };
   };
+
   template <typename Column>
   struct value_type_of<select_column_list_t<Column>> : public select_column_value_type_of<Column>
   {
diff --git a/include/sqlpp11/core/detail/type_vector.h b/include/sqlpp11/core/detail/type_vector.h
index ff7ae4eb..90bf40a0 100644
--- a/include/sqlpp11/core/detail/type_vector.h
+++ b/include/sqlpp11/core/detail/type_vector.h
@@ -27,6 +27,7 @@
  */
 
 #include <sqlpp11/core/wrong.h>
+#include <sqlpp11/core/logic.h>
 
 namespace sqlpp
 {
@@ -35,6 +36,8 @@ namespace sqlpp
     template <typename... T>
     struct type_vector
     {
+      template<typename X>
+      using contains = std::integral_constant<bool, ::sqlpp::logic::any_t<std::is_same<T, X>::value...>::value>;
     };
 
     template <typename... T>
diff --git a/include/sqlpp11/core/function/lower.h b/include/sqlpp11/core/function/lower.h
index 7adfbf72..58197b6d 100644
--- a/include/sqlpp11/core/function/lower.h
+++ b/include/sqlpp11/core/function/lower.h
@@ -51,6 +51,15 @@ namespace sqlpp
     Expr _expr;
   };
 
+  template <typename Expr>
+  struct value_type_of<lower_t<Expr>>  : public value_type_of<Expr> {};
+
+  template <typename Expr>
+  struct nodes_of<lower_t<Expr>>
+  {
+    using type = detail::type_vector<Expr>;
+  };
+
   template <typename Context, typename Expr>
   auto to_sql_string(Context& context, const lower_t<Expr>& t) -> std::string
   {
diff --git a/include/sqlpp11/core/function/upper.h b/include/sqlpp11/core/function/upper.h
index 2818d899..4f640a11 100644
--- a/include/sqlpp11/core/function/upper.h
+++ b/include/sqlpp11/core/function/upper.h
@@ -51,6 +51,15 @@ namespace sqlpp
     Expr _expr;
   };
 
+  template <typename Expr>
+  struct value_type_of<upper_t<Expr>> : public value_type_of<Expr> {};
+
+  template <typename Expr>
+  struct nodes_of<upper_t<Expr>>
+  {
+    using type = detail::type_vector<Expr>;
+  };
+
   template <typename Context, typename Expr>
   auto to_sql_string(Context& context, const upper_t<Expr>& t) -> std::string
   {
diff --git a/include/sqlpp11/core/type_traits/aggregates.h b/include/sqlpp11/core/type_traits/aggregates.h
index c20c1007..218ce85a 100644
--- a/include/sqlpp11/core/type_traits/aggregates.h
+++ b/include/sqlpp11/core/type_traits/aggregates.h
@@ -44,20 +44,22 @@ namespace sqlpp
   {
   };
 
-  // Finds group_by expressions.
+  // Finds group_by expression.
   // @GroupByExpressions: type_vector
-  template <typename T, typename GroupByExpressions>
-  struct contains_aggregate_expressions
-      : public std::integral_constant<bool, contains_aggregate_expressions<nodes_of_t<T>, GroupByExpressions>::value>
+  template <typename GroupByExpressions, typename T>
+  struct contains_aggregate_expression
+      : public std::integral_constant<bool,
+                                      GroupByExpressions::template contains<T>::value or
+                                          contains_aggregate_expression<GroupByExpressions, nodes_of_t<T>>::value>
   {
   };
 
-  template <typename... T, typename GroupByExpressions>
-  struct contains_aggregate_expressions<detail::type_vector<T...>, GroupByExpressions>
+  template <typename GroupByExpressions, typename... T>
+  struct contains_aggregate_expression<GroupByExpressions, detail::type_vector<T...>>
       : public std::integral_constant<
             bool,
             logic::any_t<(GroupByExpressions::template contains<T>::value or
-                         contains_aggregate_expressions<T, GroupByExpressions>::value)...>::value>
+                         contains_aggregate_expression<GroupByExpressions, T>::value)...>::value>
   {
   };
 
diff --git a/tests/core/types/type_traits/aggregates.cpp b/tests/core/types/type_traits/aggregates.cpp
index 66877d66..97ad0f28 100644
--- a/tests/core/types/type_traits/aggregates.cpp
+++ b/tests/core/types/type_traits/aggregates.cpp
@@ -26,37 +26,187 @@
 #include "Sample.h"
 #include <sqlpp11/sqlpp11.h>
 
+SQLPP_ALIAS_PROVIDER(cheese);
+
 void test_contains_aggregate_function()
 {
-  auto v_not_null = sqlpp::value(17);
+  auto v = sqlpp::value(17);
+  auto t = sqlpp::value("");
+  auto col_int = test::TabFoo{}.id;
+  auto col_txt = test::TabFoo{}.textNnD;
 
-#warning: Need to test contains_aggregate_function
+  // Values are aggregate neutral and therefore considered neither aggregate and non-aggregate context.
+  static_assert(not sqlpp::contains_aggregate_function<decltype(v)>::value, "");
+  static_assert(not sqlpp::contains_aggregate_function<decltype(v + v)>::value, "");
 
+  // Columns are non-aggregates.
+  static_assert(not sqlpp::contains_aggregate_function<decltype(col_int)>::value, "");
+  static_assert(not sqlpp::contains_aggregate_function<decltype(col_int + v)>::value, "");
+
+  // Normal functions of values or non-aggregates do not contain aggregate functions.
+  static_assert(not sqlpp::contains_aggregate_function<decltype(trim(t))>::value, "");
+  static_assert(not sqlpp::contains_aggregate_function<decltype(trim(col_txt))>::value, "");
+
+  // Aggregate functions of non-aggregates and values contain aggregate functions.
+  static_assert(not sqlpp::contains_non_aggregate<decltype(avg(v))>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(count(v))>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(min(v))>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(max(v))>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(sum(v))>::value, "");
+
+  static_assert(sqlpp::contains_aggregate_function<decltype(avg(col_int))>::value, "");
+  static_assert(sqlpp::contains_aggregate_function<decltype(count(col_int))>::value, "");
+  static_assert(sqlpp::contains_aggregate_function<decltype(min(col_int))>::value, "");
+  static_assert(sqlpp::contains_aggregate_function<decltype(max(col_int))>::value, "");
+  static_assert(sqlpp::contains_aggregate_function<decltype(sum(col_int))>::value, "");
+
+  static_assert(sqlpp::contains_aggregate_function<decltype(avg(col_int) + v)>::value, "");
+  static_assert(sqlpp::contains_aggregate_function<decltype(count(col_int) + v)>::value, "");
+  static_assert(sqlpp::contains_aggregate_function<decltype(min(col_int) + v)>::value, "");
+  static_assert(sqlpp::contains_aggregate_function<decltype(max(col_int) + v)>::value, "");
+  static_assert(sqlpp::contains_aggregate_function<decltype(sum(col_int) + v)>::value, "");
+
+  static_assert(sqlpp::contains_aggregate_function<decltype(trim(max(col_txt)))>::value, "");
+  static_assert(sqlpp::contains_aggregate_function<decltype(max(trim(col_txt)))>::value, "");
+
+  // Expressions of aggregate functions and non-aggregates contain aggregate functions.
+  static_assert(sqlpp::contains_aggregate_function<decltype(avg(col_int) + col_int)>::value, "");
+  static_assert(sqlpp::contains_aggregate_function<decltype(count(col_int) + col_int)>::value, "");
+  static_assert(sqlpp::contains_aggregate_function<decltype(min(col_int) + col_int)>::value, "");
+  static_assert(sqlpp::contains_aggregate_function<decltype(max(col_int) + col_int)>::value, "");
+  static_assert(sqlpp::contains_aggregate_function<decltype(sum(col_int) + col_int)>::value, "");
+
+  static_assert(sqlpp::contains_aggregate_function<decltype(trim(upper(lower(max(col_txt)))) + trim(col_txt))>::value, "");
+  static_assert(sqlpp::contains_aggregate_function<decltype(max(trim(col_txt)) + trim(col_txt))>::value, "");
+
+  // Clauses expose non-aggregates (probably irrelevant)
+  static_assert(not sqlpp::contains_aggregate_function<decltype(where(col_int > v))>::value, "");
+  static_assert(sqlpp::contains_aggregate_function<decltype(select_columns(max(col_int), v.as(cheese), col_int))>::value, "");
 }
 
 void test_contains_aggregate_expression()
 {
   auto v_not_null = sqlpp::value(17);
 
-#warning: Need to test contains_aggregate_expression
+  auto v = sqlpp::value(17);
+  auto t = sqlpp::value("");
+  auto col_int = test::TabFoo{}.id;
+  auto col_txt = test::TabFoo{}.textNnD;
+
+  using known_aggregates = sqlpp::detail::type_vector<decltype(v), decltype(col_txt), decltype(col_int + v)>;
+  using unknown = sqlpp::detail::type_vector<>;
+
+  // ...
+  static_assert(sqlpp::contains_aggregate_expression<known_aggregates, decltype(v)>::value, "");
+  static_assert(sqlpp::contains_aggregate_expression<known_aggregates, decltype(v + v)>::value, "");
+
+  // ...
+  static_assert(not sqlpp::contains_aggregate_expression<unknown, decltype(v)>::value, "");
+  static_assert(not sqlpp::contains_aggregate_expression<unknown, decltype(v + v)>::value, "");
+
+#warning: activate
+#if 0
+  // Columns are non-aggregates.
+  static_assert(not sqlpp::contains_aggregate_expression<decltype(col_int)>::value, "");
+  static_assert(not sqlpp::contains_aggregate_expression<decltype(col_int + v)>::value, "");
+
+  // Normal expressions of values or non-aggregates do not contain aggregate functions.
+  static_assert(not sqlpp::contains_aggregate_expression<decltype(trim(t))>::value, "");
+  static_assert(not sqlpp::contains_aggregate_expression<decltype(trim(col_txt))>::value, "");
+
+  // Aggregate expressions of non-aggregates contain aggregate functions.
+  static_assert(not sqlpp::contains_aggregate_expressions<decltype(avg(v))>::value, "");
+  static_assert(not sqlpp::contains_aggregate_expressions<decltype(count(v))>::value, "");
+  static_assert(not sqlpp::contains_aggregate_expressions<decltype(min(v))>::value, "");
+  static_assert(not sqlpp::contains_aggregate_expressions<decltype(max(v))>::value, "");
+  static_assert(not sqlpp::contains_aggregate_expressions<decltype(sum(v))>::value, "");
+
+  static_assert(sqlpp::contains_aggregate_expression<decltype(avg(col_int))>::value, "");
+  static_assert(sqlpp::contains_aggregate_expression<decltype(count(col_int))>::value, "");
+  static_assert(sqlpp::contains_aggregate_expression<decltype(min(col_int))>::value, "");
+  static_assert(sqlpp::contains_aggregate_expression<decltype(max(col_int))>::value, "");
+  static_assert(sqlpp::contains_aggregate_expression<decltype(sum(col_int))>::value, "");
+
+  static_assert(sqlpp::contains_aggregate_expression<decltype(avg(col_int) + v)>::value, "");
+  static_assert(sqlpp::contains_aggregate_expression<decltype(count(col_int) + v)>::value, "");
+  static_assert(sqlpp::contains_aggregate_expression<decltype(min(col_int) + v)>::value, "");
+  static_assert(sqlpp::contains_aggregate_expression<decltype(max(col_int) + v)>::value, "");
+  static_assert(sqlpp::contains_aggregate_expression<decltype(sum(col_int) + v)>::value, "");
+
+  static_assert(sqlpp::contains_aggregate_expression<decltype(trim(max(col_txt)))>::value, "");
+  static_assert(sqlpp::contains_aggregate_expression<decltype(max(trim(col_txt)))>::value, "");
+
+  // Expressions of aggregate expressions and non-aggregates contain aggregate functions.
+  static_assert(sqlpp::contains_aggregate_expression<decltype(avg(col_int) + col_int)>::value, "");
+  static_assert(sqlpp::contains_aggregate_expression<decltype(count(col_int) + col_int)>::value, "");
+  static_assert(sqlpp::contains_aggregate_expression<decltype(min(col_int) + col_int)>::value, "");
+  static_assert(sqlpp::contains_aggregate_expression<decltype(max(col_int) + col_int)>::value, "");
+  static_assert(sqlpp::contains_aggregate_expression<decltype(sum(col_int) + col_int)>::value, "");
+
+  static_assert(sqlpp::contains_aggregate_expression<decltype(trim(upper(lower(max(col_txt)))) + trim(col_txt))>::value, "");
+  static_assert(sqlpp::contains_aggregate_expression<decltype(max(trim(col_txt)) + trim(col_txt))>::value, "");
+
+  // Clauses expose non-aggregates (probably irrelevant)
+  static_assert(not sqlpp::contains_aggregate_expression<decltype(where(col_int > v))>::value, "");
+  static_assert(sqlpp::contains_aggregate_expression<decltype(select_columns(max(col_int), v.as(cheese), col_int))>::value, "");
+#endif
 
 }
 
 void test_contains_non_aggregate()
 {
   auto v = sqlpp::value(17);
-  auto col = test::TabFoo{}.id;
+  auto t = sqlpp::value("");
+  auto col_int = test::TabFoo{}.id;
+  auto col_txt = test::TabFoo{}.textNnD;
 
-  static_assert(sqlpp::contains_non_aggregate<decltype(col)>::value, "");
-  static_assert(sqlpp::contains_non_aggregate<decltype(col + v)>::value, "");
-  static_assert(not sqlpp::contains_non_aggregate<decltype(avg(col) + v)>::value, "");
-  static_assert(not sqlpp::contains_non_aggregate<decltype(count(col) + v)>::value, "");
-  static_assert(not sqlpp::contains_non_aggregate<decltype(min(col) + v)>::value, "");
-  static_assert(not sqlpp::contains_non_aggregate<decltype(max(col) + v)>::value, "");
-  static_assert(not sqlpp::contains_non_aggregate<decltype(sum(col) + v)>::value, "");
-#warning: lets test some functions, too
-#warning: lets test some clauses, too
+  // Values are aggregate neutral and therefore considered neither aggregate and non-aggregate context.
+  static_assert(not sqlpp::contains_non_aggregate<decltype(v)>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(v + v)>::value, "");
 
+  // Columns are non-aggregates.
+  static_assert(sqlpp::contains_non_aggregate<decltype(col_int)>::value, "");
+  static_assert(sqlpp::contains_non_aggregate<decltype(col_int + v)>::value, "");
+
+  // Functions can contain non-aggregates.
+  static_assert(not sqlpp::contains_non_aggregate<decltype(trim(t))>::value, "");
+  static_assert(sqlpp::contains_non_aggregate<decltype(trim(col_txt))>::value, "");
+
+  // Aggregate functions of non-aggregates and values are aggregate functions.
+  static_assert(not sqlpp::contains_non_aggregate<decltype(avg(v))>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(count(v))>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(min(v))>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(max(v))>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(sum(v))>::value, "");
+
+  static_assert(not sqlpp::contains_non_aggregate<decltype(avg(col_int))>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(count(col_int))>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(min(col_int))>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(max(col_int))>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(sum(col_int))>::value, "");
+
+  static_assert(not sqlpp::contains_non_aggregate<decltype(avg(col_int) + v)>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(count(col_int) + v)>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(min(col_int) + v)>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(max(col_int) + v)>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(sum(col_int) + v)>::value, "");
+
+  static_assert(not sqlpp::contains_non_aggregate<decltype(trim(max(col_txt)))>::value, "");
+  static_assert(not sqlpp::contains_non_aggregate<decltype(max(trim(col_txt)))>::value, "");
+
+  // Expressions of aggregate functions and non-aggregates contain non-aggregates.
+  static_assert(sqlpp::contains_non_aggregate<decltype(avg(col_int) + col_int)>::value, "");
+  static_assert(sqlpp::contains_non_aggregate<decltype(count(col_int) + col_int)>::value, "");
+  static_assert(sqlpp::contains_non_aggregate<decltype(min(col_int) + col_int)>::value, "");
+  static_assert(sqlpp::contains_non_aggregate<decltype(max(col_int) + col_int)>::value, "");
+  static_assert(sqlpp::contains_non_aggregate<decltype(sum(col_int) + col_int)>::value, "");
+
+  static_assert(sqlpp::contains_non_aggregate<decltype(trim(max(col_txt)) + trim(col_txt))>::value, "");
+  static_assert(sqlpp::contains_non_aggregate<decltype(max(trim(col_txt)) + trim(col_txt))>::value, "");
+
+  // Clauses expose non-aggregates (probably irrelevant)
+  static_assert(sqlpp::contains_non_aggregate<decltype(where(col_int > v))>::value, "");
+  static_assert(sqlpp::contains_non_aggregate<decltype(select_columns(max(col_int), v.as(cheese), col_int))>::value, "");
 }
 
 int main()