diff --git a/include/sqlpp11/aggregate_functions/count.h b/include/sqlpp11/aggregate_functions/count.h
index cf77e23a..421e8b9f 100644
--- a/include/sqlpp11/aggregate_functions/count.h
+++ b/include/sqlpp11/aggregate_functions/count.h
@@ -34,32 +34,8 @@
 
 namespace sqlpp
 {
-  struct count_alias_t
-  {
-    struct _alias_t
-    {
-      static constexpr const char _literal[] = "count_";
-      using _name_t = sqlpp::make_char_sequence<sizeof(_literal), _literal>;
-      template <typename T>
-      struct _member_t
-      {
-        T count;
-        T& operator()()
-        {
-          return count;
-        }
-        const T& operator()() const
-        {
-          return count;
-        }
-      };
-    };
-  };
-
   template <typename Flag, typename Expr>
-  struct count_t : public expression_operators<count_t<Flag, Expr>, integral>,
-                   public aggregate_function_operators<count_t<Flag, Expr>>,
-                   public alias_operators<count_t<Flag, Expr>>
+  struct count_t
   {
     using _traits = make_traits<integral, tag::is_expression /*, tag::is_selectable*/>;
 
@@ -67,11 +43,6 @@ namespace sqlpp
     using _can_be_null = std::false_type;
     using _is_aggregate_expression = std::true_type;
 
-    static_assert(is_noop<Flag>::value or std::is_same<distinct_t, Flag>::value,
-                  "count() used with flag other than 'distinct'");
-
-    using _auto_alias_t = count_alias_t;
-
     count_t(const Expr expr) : _expr(expr)
     {
     }
@@ -85,6 +56,12 @@ namespace sqlpp
     Expr _expr;
   };
 
+  template <typename Flag, typename Expr>
+  struct value_type_of<count_t<Flag, Expr>>
+  {
+    using type = integral;
+  };
+
   template <typename Context, typename Flag, typename Expr>
   Context& serialize(const count_t<Flag, Expr>& t, Context& context)
   {
@@ -100,20 +77,19 @@ namespace sqlpp
   }
 
   template <typename T>
-  auto count(T t) -> count_t<noop, wrap_operand_t<T>>
+  using check_count_arg =
+      std::enable_if_t<values_are_comparable<T, T>::value and not contains_aggregate_function_t<T>::value>;
+
+  template <typename T, typename = check_count_arg<T>>
+  auto count(T t) -> count_t<noop, T>
   {
-    static_assert(not contains_aggregate_function_t<wrap_operand_t<T>>::value,
-                  "count() cannot be used on an aggregate function");
-    static_assert(is_expression_t<wrap_operand_t<T>>::value, "count() requires an expression as argument");
-    return {t};
+    return {std::move(t)};
   }
 
-  template <typename T>
-  auto count(const distinct_t& /*unused*/, T t) -> count_t<distinct_t, wrap_operand_t<T>>
+  template <typename T, typename = check_count_arg<T>>
+  auto count(const distinct_t& /*unused*/, T t) -> count_t<distinct_t, T>
   {
-    static_assert(not contains_aggregate_function_t<wrap_operand_t<T>>::value,
-                  "count() cannot be used on an aggregate function");
-    static_assert(is_expression_t<wrap_operand_t<T>>::value, "count() requires an expression as argument");
-    return {t};
+    return {std::move(t)};
   }
+
 }  // namespace sqlpp
diff --git a/include/sqlpp11/aggregate_functions/min.h b/include/sqlpp11/aggregate_functions/min.h
index c6432bc1..1e90b2ab 100644
--- a/include/sqlpp11/aggregate_functions/min.h
+++ b/include/sqlpp11/aggregate_functions/min.h
@@ -31,40 +31,14 @@
 
 namespace sqlpp
 {
-  struct min_alias_t
-  {
-    struct _alias_t
-    {
-      static constexpr const char _literal[] = "min_";
-      using _name_t = sqlpp::make_char_sequence<sizeof(_literal), _literal>;
-      template <typename T>
-      struct _member_t
-      {
-        T min;
-        T& operator()()
-        {
-          return min;
-        }
-        const T& operator()() const
-        {
-          return min;
-        }
-      };
-    };
-  };
-
   template <typename Flag, typename Expr>
-  struct min_t : public expression_operators<min_t<Flag, Expr>, value_type_of_t<Expr>>,
-                 public aggregate_function_operators<min_t<Flag, Expr>>,
-                 public alias_operators<min_t<Flag, Expr>>
+  struct min_t
   {
     using _traits = make_traits<value_type_of_t<Expr>, tag::is_expression, tag::is_selectable>;
     using _nodes = detail::type_vector<Expr, aggregate_function>;
     using _can_be_null = std::true_type;
     using _is_aggregate_expression = std::true_type;
 
-    using _auto_alias_t = min_alias_t;
-
     min_t(Expr expr) : _expr(expr)
     {
     }
@@ -78,6 +52,12 @@ namespace sqlpp
     Expr _expr;
   };
 
+  template <typename Flag, typename Expr>
+  struct value_type_of<min_t<Flag, Expr>>
+  {
+    using type = sqlpp::force_optional_t<value_type_of_t<Expr>>;
+  };
+
   template <typename Context, typename Flag, typename Expr>
   Context& serialize(const min_t<Flag, Expr>& t, Context& context)
   {
@@ -93,20 +73,18 @@ namespace sqlpp
   }
 
   template <typename T>
-  auto min(T t) -> min_t<noop, wrap_operand_t<T>>
+  using check_min_arg =
+      std::enable_if_t<values_are_comparable<T, T>::value and not contains_aggregate_function_t<T>::value>;
+
+  template <typename T, typename = check_min_arg<T>>
+  auto min(T t) -> min_t<noop, T>
   {
-    static_assert(not contains_aggregate_function_t<wrap_operand_t<T>>::value,
-                  "min() cannot be used on an aggregate function");
-    static_assert(is_expression_t<wrap_operand_t<T>>::value, "min() requires an expression as argument");
-    return {t};
+    return {std::move(t)};
   }
 
-  template <typename T>
-  auto min(const distinct_t& /*unused*/, T t) -> min_t<distinct_t, wrap_operand_t<T>>
+  template <typename T, typename = check_min_arg<T>>
+  auto min(const distinct_t& /*unused*/, T t) -> min_t<distinct_t, T>
   {
-    static_assert(not contains_aggregate_function_t<wrap_operand_t<T>>::value,
-                  "min() cannot be used on an aggregate function");
-    static_assert(is_expression_t<wrap_operand_t<T>>::value, "min() requires an expression as argument");
-    return {t};
+    return {std::move(t)};
   }
 }  // namespace sqlpp
diff --git a/include/sqlpp11/operator/arithmetic_expression.h b/include/sqlpp11/operator/arithmetic_expression.h
index 29d1a6ce..159a6881 100644
--- a/include/sqlpp11/operator/arithmetic_expression.h
+++ b/include/sqlpp11/operator/arithmetic_expression.h
@@ -66,7 +66,7 @@ namespace sqlpp
   };
 
   template <typename L, typename R>
-  using check_arithmetic_args = std::enable_if_t<has_numeric_value<L>::value and has_numeric_value<R>::value>;
+  using check_arithmetic_args = std::enable_if_t<is_numeric<L>::value and is_numeric<R>::value>;
 
 #warning: need to document that this is on purpose (not integral, or unsigned integral, or floating_point) because it is difficult to know for the library to know what the actual result type will be (it is difficult to guess in C++ already, and it is probably different from DB vendor to vendor).
   template <typename L, typename Operator, typename R>
diff --git a/include/sqlpp11/type_traits.h b/include/sqlpp11/type_traits.h
index e5672b59..0a314a6b 100644
--- a/include/sqlpp11/type_traits.h
+++ b/include/sqlpp11/type_traits.h
@@ -127,7 +127,7 @@ namespace sqlpp
   template<typename T>
   struct value_type_of<sqlpp::compat::optional<T>>
   {
-    using type = sqlpp::compat::optional<value_type_of_t<remove_optional_t<T>>>;
+    using type = sqlpp::force_optional_t<value_type_of_t<remove_optional_t<T>>>;
   };
 
   template <typename T>
@@ -232,10 +232,23 @@ namespace sqlpp
   struct is_unsigned_integral<sqlpp::compat::nullopt_t> : public std::true_type {
   };
 
+  template <typename T>
+  struct is_floating_point : public std::is_same<remove_optional_t<value_type_of_t<T>>, floating_point>
+  {
+  };
+
+  template <>
+  struct is_floating_point<sqlpp::compat::nullopt_t> : public std::true_type {
+  };
+
   // A generic numeric type which could be (unsigned) integral or floating point.
   struct numeric;
   template <typename T>
-  struct is_numeric : public std::integral_constant<bool, is_integral<T>::value or is_unsigned_integral<T>::value or std::is_floating_point<T>::value>{};
+  struct is_numeric : public std::integral_constant<bool,
+                                                    is_integral<T>::value or is_unsigned_integral<T>::value or
+                                                        is_floating_point<T>::value>
+  {
+  };
 
   template <>
   struct is_numeric<numeric> : public std::true_type{};
@@ -244,125 +257,64 @@ namespace sqlpp
   struct is_numeric<sqlpp::compat::nullopt_t> : public std::true_type{};
 
   template <typename T>
-  struct has_numeric_value : public std::integral_constant<bool,
-      is_numeric<remove_optional_t<T>>::value or is_numeric<remove_optional_t<value_type_of_t<T>>>::value>{};
-
-  struct text;
-  template <typename T>
-  struct is_text : public std::false_type {};
-
-  template <>
-  struct is_text<text> : public std::true_type {};
-
-  template <>
-  struct is_text<char> : public std::true_type {};
-
-  template <>
-  struct is_text<const char*> : public std::true_type {};
-
-  template <>
-  struct is_text<std::string> : public std::true_type {};
-
-  template <>
-  struct is_text<sqlpp::compat::string_view> : public std::true_type {};
-
-  template <>
-  struct is_text<sqlpp::compat::nullopt_t> : public std::true_type {};
-
-  template <typename T>
-  struct has_text_value : public std::integral_constant<bool,
-                                                        is_text<remove_optional_t<T>>::value or
-                                                            is_text<remove_optional_t<value_type_of_t<T>>>::value>{};
-
-  struct blob;
-  template <typename T>
-  struct is_blob : public std::false_type {};
-
-  template <>
-  struct is_blob<blob> : public std::true_type {};
-
-  template <>
-  struct is_blob<std::vector<std::uint8_t>> : public std::true_type {};
-
-  template <>
-  struct is_blob<sqlpp::compat::span<std::uint8_t>> : public std::true_type {};
-
-  template <>
-  struct is_blob<sqlpp::compat::nullopt_t> : public std::true_type {};
-
-  template <typename T>
-  struct has_blob_value : public std::integral_constant<bool,
-                                                        is_blob<remove_optional_t<T>>::value or
-                                                            is_blob<remove_optional_t<value_type_of_t<T>>>::value>{};
-
-  struct day_point;
-  template <typename T>
-  struct is_day_point : public std::false_type {};
-
-  template <>
-  struct is_day_point<day_point> : public std::true_type {};
-
-  template <>
-  struct is_day_point<std::chrono::time_point<std::chrono::system_clock, sqlpp::chrono::days>> : public std::true_type {};
-
-  template <>
-  struct is_day_point<sqlpp::compat::nullopt_t> : public std::true_type {};
-
-  template <typename T>
-  struct has_day_point_value : public std::integral_constant<bool,
-                                                        is_day_point<remove_optional_t<T>>::value or
-                                                            is_day_point<remove_optional_t<value_type_of_t<T>>>::value>{};
-
-  struct time_of_day;
-  template <typename T>
-  struct is_time_of_day : public std::false_type {};
-
-  template <>
-  struct is_time_of_day<time_of_day> : public std::true_type {};
-
-  template <typename Rep, typename Period>
-  struct is_time_of_day<std::chrono::duration<Rep, Period>> : public std::true_type {};
-
-  template <>
-  struct is_time_of_day<sqlpp::compat::nullopt_t> : public std::true_type {};
-
-  template <typename T>
-  struct has_time_of_day_value : public std::integral_constant<bool,
-                                                        is_time_of_day<remove_optional_t<T>>::value or
-                                                            is_time_of_day<remove_optional_t<value_type_of_t<T>>>::value>{};
-
-  struct time_point;
-  template <typename T>
-  struct is_time_point : public std::false_type {};
-
-  template <>
-  struct is_time_point<time_point> : public std::true_type {};
-
-  template <typename Period>
-  struct is_time_point<std::chrono::time_point<std::chrono::system_clock, Period>> : public std::true_type {};
-
-  template <>
-  struct is_time_point<sqlpp::compat::nullopt_t> : public std::true_type {};
-
-  template <typename T>
-  struct has_time_point_value : public std::integral_constant<bool,
-                                                        is_time_point<remove_optional_t<T>>::value or
-                                                            is_time_point<remove_optional_t<value_type_of_t<T>>>::value>{};
-
-#warning: Need to add float and unsigned traits?
-  template <typename L, typename R>
-  struct values_are_comparable
-      : public std::integral_constant<bool,
-                                      (has_blob_value<L>::value and has_blob_value<R>::value) or
-                                          (is_boolean<L>::value and is_boolean<R>::value) or
-                                          (has_day_point_value<L>::value and has_day_point_value<R>::value) or
-                                          (has_numeric_value<L>::value and has_numeric_value<R>::value) or
-                                          (has_text_value<L>::value and has_text_value<R>::value) or
-                                          (has_time_of_day_value<L>::value and has_time_of_day_value<R>::value) or
-                                          (has_time_point_value<L>::value and has_time_point_value<R>::value)>
+  struct is_text : public std::is_same<remove_optional_t<value_type_of_t<T>>, text>
   {
   };
 
+  template <>
+  struct is_text<sqlpp::compat::nullopt_t> : public std::true_type {
+  };
+
+  template <typename T>
+  struct is_blob : public std::is_same<remove_optional_t<value_type_of_t<T>>, blob>
+  {
+  };
+
+  template <>
+  struct is_blob<sqlpp::compat::nullopt_t> : public std::true_type {
+  };
+
+  template <typename T>
+  struct is_day_point : public std::is_same<remove_optional_t<value_type_of_t<T>>, day_point>
+  {
+  };
+
+  template <>
+  struct is_day_point<sqlpp::compat::nullopt_t> : public std::true_type {
+  };
+
+  template <typename T>
+  struct is_time_point : public std::is_same<remove_optional_t<value_type_of_t<T>>, time_point>
+  {
+  };
+
+  template <>
+  struct is_time_point<sqlpp::compat::nullopt_t> : public std::true_type {
+  };
+
+  template <typename T>
+  struct is_time_of_day : public std::is_same<remove_optional_t<value_type_of_t<T>>, time_of_day>
+  {
+  };
+
+  template <>
+  struct is_time_of_day<sqlpp::compat::nullopt_t> : public std::true_type {
+  };
+
+  template <typename L, typename R>
+  struct values_are_comparable
+      : public std::integral_constant<bool,
+                                      (is_blob<L>::value and is_blob<R>::value) or
+                                          (is_boolean<L>::value and is_boolean<R>::value) or
+                                          (is_day_point<L>::value and is_day_point<R>::value) or
+                                          (is_numeric<L>::value and is_numeric<R>::value) or
+                                          (is_text<L>::value and is_text<R>::value) or
+                                          (is_time_of_day<L>::value and is_time_of_day<R>::value) or
+                                          (is_time_point<L>::value and is_time_point<R>::value)>
+  {
+  };
+
+#warning: These something_t data type classifiers should be removed
   // data types
   struct blob;
   template <typename T>
@@ -400,7 +352,6 @@ namespace sqlpp
   using is_time_point_t = std::is_same<value_type_of_t<T>, time_point>;
 
   // joined data type
-#warning: These something_t data type classifiers should be removed
   template <typename T>
   using is_numeric_t =
       logic::any_t<is_integral_t<T>::value, is_unsigned_integral_t<T>::value, is_floating_point_t<T>::value>;
diff --git a/tests/core/types/CMakeLists.txt b/tests/core/types/CMakeLists.txt
index 2dea1a04..a4f431ad 100644
--- a/tests/core/types/CMakeLists.txt
+++ b/tests/core/types/CMakeLists.txt
@@ -34,4 +34,10 @@ function(test_compile name)
     endif()
 endfunction()
 
-test_compile(result_row)
\ No newline at end of file
+test_compile(aggregate_functions)
+test_compile(comparison_expression)
+test_compile(in_expression)
+test_compile(logical_expression)
+test_compile(result_row)
+test_compile(value)
+
diff --git a/tests/core/types/aggregate_functions.cpp b/tests/core/types/aggregate_functions.cpp
new file mode 100644
index 00000000..13c0478b
--- /dev/null
+++ b/tests/core/types/aggregate_functions.cpp
@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2016-2016, 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 "MockDb.h"
+#include "Sample.h"
+#include <sqlpp11/sqlpp11.h>
+
+namespace
+{
+  auto db = MockDb{};
+
+  template <typename T, typename V>
+  using is_same_type = std::is_same<sqlpp::value_type_of_t<T>, V>;
+}
+
+template <typename Value>
+void test_aggregate_functions(Value v)
+{
+  auto v_not_null = sqlpp::value(v);
+  auto v_maybe_null = sqlpp::value(sqlpp::compat::make_optional(v));
+
+  using ValueType = sqlpp::value_type_of_t<Value>;
+  using OptValueType = sqlpp::value_type_of_t<sqlpp::compat::optional<Value>>;
+
+  // Aggregate of non-nullable
+  static_assert(is_same_type<decltype(count(v_not_null)), sqlpp::integral>::value, "");
+  static_assert(is_same_type<decltype(max(v_not_null)), OptValueType>::value, "");
+  static_assert(is_same_type<decltype(min(v_not_null)), OptValueType>::value, "");
+
+  // Aggregate of nullable
+  static_assert(is_same_type<decltype(count(v_not_null)), sqlpp::integral>::value, "");
+  static_assert(is_same_type<decltype(max(v_maybe_null)), OptValueType>::value, "");
+  static_assert(is_same_type<decltype(min(v_maybe_null)), OptValueType>::value, "");
+
+}
+
+int main()
+{
+  // boolean
+  test_aggregate_functions(bool{true});
+
+  // integral
+  test_aggregate_functions(int8_t{7});
+  test_aggregate_functions(int16_t{7});
+  test_aggregate_functions(int32_t{7});
+  test_aggregate_functions(int64_t{7});
+
+  // unsigned integral
+  test_aggregate_functions(uint8_t{7});
+  test_aggregate_functions(uint16_t{7});
+  test_aggregate_functions(uint32_t{7});
+  test_aggregate_functions(uint64_t{7});
+
+  // floating point
+  test_aggregate_functions(float{7.7});
+  test_aggregate_functions(double{7.7});
+
+  // text
+  test_aggregate_functions('7');
+  test_aggregate_functions("seven");
+  test_aggregate_functions(std::string("seven"));
+  test_aggregate_functions(sqlpp::compat::string_view("seven"));
+
+  // blob
+  test_aggregate_functions(std::vector<uint8_t>{});
+
+  // date
+  test_aggregate_functions(::sqlpp::chrono::day_point{});
+
+  // timestamp
+  test_aggregate_functions(::sqlpp::chrono::microsecond_point{});
+  using minute_point = std::chrono::time_point<std::chrono::system_clock, std::chrono::minutes>;
+  test_aggregate_functions(minute_point{});
+
+  // time_of_day
+  test_aggregate_functions(std::chrono::microseconds{});
+}
+
diff --git a/tests/core/types/comparison_expression.cpp b/tests/core/types/comparison_expression.cpp
new file mode 100644
index 00000000..a8f0473c
--- /dev/null
+++ b/tests/core/types/comparison_expression.cpp
@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) 2016-2016, 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 "MockDb.h"
+#include "Sample.h"
+#include <sqlpp11/sqlpp11.h>
+
+namespace
+{
+  auto db = MockDb{};
+
+  template <typename T>
+  using is_bool = std::is_same<sqlpp::value_type_of_t<T>, sqlpp::boolean>;
+
+  template <typename T>
+  using is_maybe_bool = std::is_same<sqlpp::value_type_of_t<T>, sqlpp::compat::optional<sqlpp::boolean>>;
+}
+
+template <typename Value>
+void test_comparison_expression(Value v)
+{
+  using OptValue = sqlpp::compat::optional<Value>;
+
+  auto v_not_null = sqlpp::value(v);
+  auto v_maybe_null = sqlpp::value(sqlpp::compat::make_optional(v));
+
+#warning : Should also implement like, is_null, is_distinct_from as member functions.
+
+  // Compare non-nullable with non-nullable.
+  static_assert(is_bool<decltype(v_not_null < v_not_null)>::value, "");
+  static_assert(is_bool<decltype(v_not_null <= v_not_null)>::value, "");
+  static_assert(is_bool<decltype(v_not_null == v_not_null)>::value, "");
+  static_assert(is_bool<decltype(v_not_null != v_not_null)>::value, "");
+  static_assert(is_bool<decltype(v_not_null == v_not_null)>::value, "");
+  static_assert(is_bool<decltype(v_not_null >= v_not_null)>::value, "");
+  static_assert(is_bool<decltype(v_not_null > v_not_null)>::value, "");
+  static_assert(is_bool<decltype(is_distinct_from(v_not_null, v_not_null))>::value, "");
+  static_assert(is_bool<decltype(is_not_distinct_from(v_not_null, v_not_null))>::value, "");
+
+  // Compare non-nullable with nullable.
+  static_assert(is_maybe_bool<decltype(v_not_null < v_maybe_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_not_null <= v_maybe_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_not_null == v_maybe_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_not_null != v_maybe_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_not_null == v_maybe_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_not_null >= v_maybe_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_not_null > v_maybe_null)>::value, "");
+  static_assert(is_bool<decltype(is_distinct_from(v_not_null, v_maybe_null))>::value, "");
+  static_assert(is_bool<decltype(is_not_distinct_from(v_not_null, v_maybe_null))>::value, "");
+
+  // Compare nullable with non-nullable.
+  static_assert(is_maybe_bool<decltype(v_maybe_null < v_not_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_maybe_null <= v_not_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_maybe_null == v_not_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_maybe_null != v_not_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_maybe_null == v_not_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_maybe_null >= v_not_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_maybe_null > v_not_null)>::value, "");
+  static_assert(is_bool<decltype(is_distinct_from(v_maybe_null, v_not_null))>::value, "");
+  static_assert(is_bool<decltype(is_not_distinct_from(v_maybe_null, v_not_null))>::value, "");
+
+  // Compare nullable with nullable.
+  static_assert(is_maybe_bool<decltype(v_maybe_null < v_maybe_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_maybe_null <= v_maybe_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_maybe_null == v_maybe_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_maybe_null != v_maybe_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_maybe_null == v_maybe_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_maybe_null >= v_maybe_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_maybe_null > v_maybe_null)>::value, "");
+  static_assert(is_bool<decltype(is_distinct_from(v_maybe_null, v_maybe_null))>::value, "");
+  static_assert(is_bool<decltype(is_not_distinct_from(v_maybe_null, v_maybe_null))>::value, "");
+
+  // Compare with null.
+  static_assert(is_bool<decltype(is_null(v_not_null))>::value, "");
+  static_assert(is_bool<decltype(is_null(v_maybe_null))>::value, "");
+  static_assert(is_bool<decltype(is_not_null(v_maybe_null))>::value, "");
+  static_assert(is_bool<decltype(is_not_null(v_not_null))>::value, "");
+}
+
+template<typename Value>
+void test_like(Value v)
+{
+  auto v_not_null= sqlpp::value(v);
+  auto v_maybe_null= sqlpp::value(sqlpp::compat::make_optional(v));
+
+  // Compare non-nullable with non-nullable.
+  static_assert(is_bool<decltype(like(v_not_null, v_not_null))>::value, "");
+
+  // Compare non-nullable with nullable.
+  static_assert(is_maybe_bool<decltype(like(v_not_null, v_maybe_null))>::value, "");
+
+  // Compare nullable with non-nullable.
+  static_assert(is_maybe_bool<decltype(like(v_maybe_null, v_not_null))>::value, "");
+
+  // Compare nullable with nullable.
+  static_assert(is_maybe_bool<decltype(like(v_maybe_null, v_maybe_null))>::value, "");
+}
+
+int main()
+{
+  // boolean
+  test_comparison_expression(bool{true});
+
+  // integral
+  test_comparison_expression(int8_t{7});
+  test_comparison_expression(int16_t{7});
+  test_comparison_expression(int32_t{7});
+  test_comparison_expression(int64_t{7});
+
+  // unsigned integral
+  test_comparison_expression(uint8_t{7});
+  test_comparison_expression(uint16_t{7});
+  test_comparison_expression(uint32_t{7});
+  test_comparison_expression(uint64_t{7});
+
+  // floating point
+  test_comparison_expression(float{7.7});
+  test_comparison_expression(double{7.7});
+
+  // text
+  test_comparison_expression('7');
+  test_comparison_expression("seven");
+  test_comparison_expression(std::string("seven"));
+  test_comparison_expression(sqlpp::compat::string_view("seven"));
+
+  // blob
+  test_comparison_expression(std::vector<uint8_t>{});
+
+  // date
+  test_comparison_expression(::sqlpp::chrono::day_point{});
+
+  // timestamp
+  test_comparison_expression(::sqlpp::chrono::microsecond_point{});
+  using minute_point = std::chrono::time_point<std::chrono::system_clock, std::chrono::minutes>;
+  test_comparison_expression(minute_point{});
+
+  // time_of_day
+  test_comparison_expression(std::chrono::microseconds{});
+
+  // text
+  test_like('7');
+  test_like("seven");
+  test_like(std::string("seven"));
+  test_like(sqlpp::compat::string_view("seven"));
+
+}
+
diff --git a/tests/core/types/in_expression.cpp b/tests/core/types/in_expression.cpp
new file mode 100644
index 00000000..952ae062
--- /dev/null
+++ b/tests/core/types/in_expression.cpp
@@ -0,0 +1,136 @@
+/*
+ * Copyright (c) 2016-2016, 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 "MockDb.h"
+#include "Sample.h"
+#include <sqlpp11/sqlpp11.h>
+
+namespace
+{
+  auto db = MockDb{};
+
+  template <typename T>
+  using is_bool = std::is_same<sqlpp::value_type_of_t<T>, sqlpp::boolean>;
+
+  template <typename T>
+  using is_maybe_bool = std::is_same<sqlpp::value_type_of_t<T>, sqlpp::compat::optional<sqlpp::boolean>>;
+}
+
+template <typename Value>
+void test_in_expression(Value v)
+{
+  using OptValue = sqlpp::compat::optional<Value>;
+
+  auto v_not_null = sqlpp::value(v);
+  auto v_maybe_null = sqlpp::value(sqlpp::compat::make_optional(v));
+
+#warning : Need to support in with select
+  // in(v_not_null, select(v_not_null.as(sqlpp::alias::a)));
+
+  // Compare non-nullable with non-nullable.
+  static_assert(is_bool<decltype(in(v_not_null, std::make_tuple(v_not_null, v_not_null)))>::value, "");
+  static_assert(is_bool<decltype(in(v_not_null, std::vector<Value>{}))>::value, "");
+
+  // Compare non-nullable with nullable.
+  static_assert(is_maybe_bool<decltype(in(v_not_null, std::make_tuple(v_not_null, v_maybe_null)))>::value, "");
+  static_assert(is_maybe_bool<decltype(in(v_not_null, std::vector<OptValue>{}))>::value, "");
+
+  // Compare nullable with non-nullable.
+  static_assert(is_maybe_bool<decltype(in(v_maybe_null, std::make_tuple(v_not_null, v_not_null)))>::value, "");
+  static_assert(is_maybe_bool<decltype(in(v_maybe_null, std::vector<Value>{}))>::value, "");
+
+  // Compare nullable with nullable.
+  static_assert(is_maybe_bool<decltype(in(v_maybe_null, std::make_tuple(v_not_null, v_maybe_null)))>::value, "");
+  static_assert(is_maybe_bool<decltype(in(v_maybe_null, std::vector<OptValue>{}))>::value, "");
+}
+
+template<typename Value>
+void test_like(Value v)
+{
+  auto v_not_null= sqlpp::value(v);
+  auto v_maybe_null= sqlpp::value(sqlpp::compat::make_optional(v));
+
+  // Compare non-nullable with non-nullable.
+  static_assert(is_bool<decltype(like(v_not_null, v_not_null))>::value, "");
+
+  // Compare non-nullable with nullable.
+  static_assert(is_maybe_bool<decltype(like(v_not_null, v_maybe_null))>::value, "");
+
+  // Compare nullable with non-nullable.
+  static_assert(is_maybe_bool<decltype(like(v_maybe_null, v_not_null))>::value, "");
+
+  // Compare nullable with nullable.
+  static_assert(is_maybe_bool<decltype(like(v_maybe_null, v_maybe_null))>::value, "");
+}
+
+int main()
+{
+  // boolean
+  test_in_expression(bool{true});
+
+  // integral
+  test_in_expression(int8_t{7});
+  test_in_expression(int16_t{7});
+  test_in_expression(int32_t{7});
+  test_in_expression(int64_t{7});
+
+  // unsigned integral
+  test_in_expression(uint8_t{7});
+  test_in_expression(uint16_t{7});
+  test_in_expression(uint32_t{7});
+  test_in_expression(uint64_t{7});
+
+  // floating point
+  test_in_expression(float{7.7});
+  test_in_expression(double{7.7});
+
+  // text
+  test_in_expression('7');
+  test_in_expression("seven");
+  test_in_expression(std::string("seven"));
+  test_in_expression(sqlpp::compat::string_view("seven"));
+
+  // blob
+  test_in_expression(std::vector<uint8_t>{});
+
+  // date
+  test_in_expression(::sqlpp::chrono::day_point{});
+
+  // timestamp
+  test_in_expression(::sqlpp::chrono::microsecond_point{});
+  using minute_point = std::chrono::time_point<std::chrono::system_clock, std::chrono::minutes>;
+  test_in_expression(minute_point{});
+
+  // time_of_day
+  test_in_expression(std::chrono::microseconds{});
+
+  // text
+  test_like('7');
+  test_like("seven");
+  test_like(std::string("seven"));
+  test_like(sqlpp::compat::string_view("seven"));
+
+}
+
diff --git a/tests/core/types/logical_expression.cpp b/tests/core/types/logical_expression.cpp
new file mode 100644
index 00000000..b2f538f6
--- /dev/null
+++ b/tests/core/types/logical_expression.cpp
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2016-2016, 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 "MockDb.h"
+#include "Sample.h"
+#include <sqlpp11/sqlpp11.h>
+
+namespace
+{
+  auto db = MockDb{};
+
+  template <typename T>
+  using is_bool = std::is_same<sqlpp::value_type_of_t<T>, sqlpp::boolean>;
+
+  template <typename T>
+  using is_maybe_bool = std::is_same<sqlpp::value_type_of_t<T>, sqlpp::compat::optional<sqlpp::boolean>>;
+}
+
+template<typename Value>
+void test_logical_expression(Value v)
+{
+  auto v_not_null= sqlpp::value(v);
+  auto v_maybe_null= sqlpp::value(sqlpp::compat::make_optional(v));
+
+  // Compare non-nullable with non-nullable.
+  static_assert(is_bool<decltype(v_not_null and v_not_null)>::value, "");
+  static_assert(is_bool<decltype(v_not_null or v_not_null)>::value, "");
+
+  // Compare non-nullable with nullable.
+  static_assert(is_maybe_bool<decltype(v_maybe_null and v_not_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_maybe_null or v_not_null)>::value, "");
+
+  // Compare nullable with non-nullable.
+  static_assert(is_maybe_bool<decltype(v_not_null and v_maybe_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_not_null or v_maybe_null)>::value, "");
+
+  // Compare nullable with nullable.
+  static_assert(is_maybe_bool<decltype(v_maybe_null and v_maybe_null)>::value, "");
+  static_assert(is_maybe_bool<decltype(v_maybe_null or v_maybe_null)>::value, "");
+
+  // not.
+  static_assert(is_bool<decltype(not(v_not_null))>::value, "");
+  static_assert(is_maybe_bool<decltype(not(v_maybe_null))>::value, "");
+}
+
+int main()
+{
+  // boolean
+  test_logical_expression(bool{true});
+}
+
diff --git a/tests/core/types/result_row.cpp b/tests/core/types/result_row.cpp
index 9981231b..9110476b 100644
--- a/tests/core/types/result_row.cpp
+++ b/tests/core/types/result_row.cpp
@@ -42,193 +42,73 @@ namespace
   auto db = MockDb{};
 }
 
+SQLPP_ALIAS_PROVIDER(r_not_null);
+SQLPP_ALIAS_PROVIDER(r_maybe_null);
+SQLPP_ALIAS_PROVIDER(r_opt_not_null);
+SQLPP_ALIAS_PROVIDER(r_opt_maybe_null);
+
+template<typename ResultType, typename Value>
+void test_result_row(Value v)
+{
+  using OptResultType = sqlpp::compat::optional<ResultType>;
+
+  // Selectable values.
+  auto v_not_null = sqlpp::value(v).as(r_not_null);
+  const auto v_maybe_null = sqlpp::value(sqlpp::compat::make_optional(v)).as(r_maybe_null);
+
+  // Optional selectable values.
+  const auto v_opt_not_null = sqlpp::value(v).as(r_opt_not_null).if_(true);
+  const auto v_opt_maybe_null = sqlpp::value(sqlpp::compat::make_optional(v)).as(r_opt_maybe_null).if_(true);
+
+  for (const auto& row : db(select(v_not_null, v_maybe_null, v_opt_not_null, v_opt_maybe_null)))
+  {
+    static_assert(std::is_same<decltype(row.r_not_null), ResultType>::value, "");
+    static_assert(std::is_same<decltype(row.r_maybe_null), OptResultType>::value, "");
+    static_assert(std::is_same<decltype(row.r_opt_not_null), OptResultType>::value, "");
+    static_assert(std::is_same<decltype(row.r_opt_maybe_null), OptResultType>::value, "");
+  }
+}
+
 int main()
 {
-  static_assert(not sqlpp::can_be_null<decltype(bar.id)>::value, "");
-  static_assert(sqlpp::can_be_null<decltype(foo.doubleN)>::value, "");
-  static_assert(not sqlpp::can_be_null<decltype(foo.textNnD)>::value, "");
-  static_assert(not sqlpp::can_be_null<decltype(bar.boolNn)>::value, "");
-  const auto seven = sqlpp::value(7).as(sqlpp::alias::s);
-  static_assert(not sqlpp::can_be_null<decltype(seven)>::value, "");
+  // boolean
+  test_result_row<bool>(bool{true});
 
-  // Select non-optional column or alias of it.
-  for (const auto& row : db(select(foo.id, foo.id.as(sqlpp::alias::a), foo.textNnD, foo.textNnD.as(sqlpp::alias::b))
-                                .from(foo)
-                                .unconditionally()))
-  {
-    static_assert(is_same_type<decltype(row.id), int64_t>(), "");
-    static_assert(is_same_type<decltype(row.a), int64_t>(), "");
-    static_assert(is_same_type<decltype(row.textNnD), sqlpp::compat::string_view>(), "");
-    static_assert(is_same_type<decltype(row.b), sqlpp::compat::string_view>(), "");
-  }
+  // integral
+  test_result_row<int64_t>(int8_t{7});
+  test_result_row<int64_t>(int16_t{7});
+  test_result_row<int64_t>(int32_t{7});
+  test_result_row<int64_t>(int64_t{7});
 
-  // Optionally select non-optional column or alias of it.
-  for (const auto& row : db(select(foo.id.if_(true), foo.id.as(sqlpp::alias::a).if_(true), foo.textNnD.if_(true),
-                                   foo.textNnD.as(sqlpp::alias::b).if_(true))
-                                .from(foo)
-                                .unconditionally()))
-  {
-    static_assert(is_same_type<decltype(row.id), sqlpp::compat::optional<int64_t>>(), "");
-    static_assert(is_same_type<decltype(row.a), sqlpp::compat::optional<int64_t>>(), "");
-    static_assert(is_same_type<decltype(row.textNnD), sqlpp::compat::optional<sqlpp::compat::string_view>>(), "");
-    static_assert(is_same_type<decltype(row.b), sqlpp::compat::optional<sqlpp::compat::string_view>>(), "");
-  }
+  // unsigned integral
+  test_result_row<uint64_t>(uint8_t{7});
+  test_result_row<uint64_t>(uint16_t{7});
+  test_result_row<uint64_t>(uint32_t{7});
+  test_result_row<uint64_t>(uint64_t{7});
 
-  // Select optional column or alias of it.
-  for (const auto& row : db(select(bar.intN, bar.intN.as(sqlpp::alias::a), bar.textN, bar.textN.as(sqlpp::alias::b))
-                                .from(bar)
-                                .unconditionally()))
-  {
-    static_assert(is_same_type<decltype(row.intN), sqlpp::compat::optional<int64_t>>(), "");
-    static_assert(is_same_type<decltype(row.a), sqlpp::compat::optional<int64_t>>(), "");
-    static_assert(is_same_type<decltype(row.textN), sqlpp::compat::optional<sqlpp::compat::string_view>>(), "");
-    static_assert(is_same_type<decltype(row.b), sqlpp::compat::optional<sqlpp::compat::string_view>>(), "");
-  }
+  // floating point
+  test_result_row<double>(float{7.7});
+  test_result_row<double>(double{7.7});
 
-  // Optionally select optional column or alias of it.
-  for (const auto& row : db(select(bar.intN.if_(true), bar.intN.as(sqlpp::alias::a).if_(true), bar.textN.if_(true),
-                                   bar.textN.as(sqlpp::alias::b).if_(true))
-                                .from(bar)
-                                .unconditionally()))
-  {
-    // optional optional are still represented as one level of optional
-    static_assert(is_same_type<decltype(row.intN), sqlpp::compat::optional<int64_t>>(), "");
-    static_assert(is_same_type<decltype(row.a), sqlpp::compat::optional<int64_t>>(), "");
-    static_assert(is_same_type<decltype(row.textN), sqlpp::compat::optional<sqlpp::compat::string_view>>(), "");
-    static_assert(is_same_type<decltype(row.b), sqlpp::compat::optional<sqlpp::compat::string_view>>(), "");
-  }
+  // text
+  test_result_row<sqlpp::compat::string_view>('7');
+  test_result_row<sqlpp::compat::string_view>("seven");
+  test_result_row<sqlpp::compat::string_view>(std::string("seven"));
+  test_result_row<sqlpp::compat::string_view>(sqlpp::compat::string_view("seven"));
 
-  // Select value and optional value.
-  for (const auto& row : db(select(sqlpp::value(7).as(sqlpp::alias::a),
-                                   sqlpp::value(sqlpp::compat::optional<int>(7)).as(sqlpp::alias::b))))
-  {
-    static_assert(is_same_type<decltype(row.a), int64_t>(), "");
-    static_assert(is_same_type<decltype(row.b), sqlpp::compat::optional<int64_t>>(), "");
-  }
+  // blob
+  test_result_row<sqlpp::compat::span<uint8_t>>(std::vector<uint8_t>{});
 
-#warning: also test with optional
-  static_assert(sqlpp::is_boolean<bool>::value, "");
-  static_assert(sqlpp::is_boolean<decltype(bar.boolNn)>::value, "");
-  static_assert(sqlpp::has_text_value<decltype(bar.textN)>::value, "");
-  static_assert(sqlpp::has_text_value<std::string>::value, "");
-  static_assert(sqlpp::has_numeric_value<int>::value, "");
-  static_assert(sqlpp::has_numeric_value<decltype(bar.intN)>::value, "");
+  // date
+  test_result_row<::sqlpp::chrono::day_point>(::sqlpp::chrono::day_point{});
 
-#warning: These should be moved into comparison type requirement tests, etc.
-  // Comparing optional value with non-optional value yields optional boolean.
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(bar.textN < "hansi")>,
-                             sqlpp::compat::optional<sqlpp::boolean>>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(bar.textN <= "hansi")>,
-                             sqlpp::compat::optional<sqlpp::boolean>>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(bar.textN == "hansi")>,
-                             sqlpp::compat::optional<sqlpp::boolean>>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(bar.textN != "hansi")>,
-                             sqlpp::compat::optional<sqlpp::boolean>>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(bar.textN >= "hansi")>,
-                             sqlpp::compat::optional<sqlpp::boolean>>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(bar.textN < "hansi")>,
-                             sqlpp::compat::optional<sqlpp::boolean>>::value,
-                "");
+  // timestamp
+  test_result_row<::sqlpp::chrono::microsecond_point>(::sqlpp::chrono::microsecond_point{});
+  using minute_point = std::chrono::time_point<std::chrono::system_clock, std::chrono::minutes>;
+  test_result_row<::sqlpp::chrono::microsecond_point>(minute_point{});
 
-  // Comparing non-optional value with non-optional value yields non-optional boolean.
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(foo.textNnD < "hansi")>,
-                             sqlpp::boolean>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(foo.textNnD <= "hansi")>,
-                             sqlpp::boolean>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(foo.textNnD == "hansi")>,
-                             sqlpp::boolean>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(foo.textNnD != "hansi")>,
-                             sqlpp::boolean>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(foo.textNnD >= "hansi")>,
-                             sqlpp::boolean>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(foo.textNnD < "hansi")>,
-                             sqlpp::boolean>::value,
-                "");
-
-  // The first exceptions are the operators is_null and is_not_null which always yield non-optional boolean
-#warning: Still need to implement is_distinct_from as member function
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(is_null(bar.textN))>,
-                             sqlpp::boolean>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(is_null(foo.textNnD))>,
-                             sqlpp::boolean>::value,
-                "");
-
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(is_not_null(bar.textN))>,
-                             sqlpp::boolean>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(is_not_null(foo.textNnD))>,
-                             sqlpp::boolean>::value,
-                "");
-
-  // The other exceptions are the operators is_distinct_from and is_not_distinct_from which always yield non-optional boolean
-#warning: Still need to implement is_distinct_from as member function
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(is_distinct_from(bar.textN, "hansi"))>,
-                             sqlpp::boolean>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(is_distinct_from(foo.textNnD, "hansi"))>,
-                             sqlpp::boolean>::value,
-                "");
-
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(is_not_distinct_from(bar.textN, sqlpp::compat::make_optional("hansi")))>,
-                             sqlpp::boolean>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(is_not_distinct_from(foo.textNnD, sqlpp::compat::make_optional("hansi")))>,
-                             sqlpp::boolean>::value,
-                "");
-
-
-  // LIKE expressions can be NULL is one of their operands can be NULL.
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(like(bar.textN, "hansi"))>, sqlpp::compat::optional<sqlpp::boolean>>::value, "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(like(foo.textNnD, sqlpp::compat::make_optional("hansi")))>, sqlpp::compat::optional<sqlpp::boolean>>::value, "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(like(foo.textNnD, "hansi"))>, sqlpp::boolean>::value, "");
-
-#warning: These should be moved into logical type requirement tests, etc.
-  // Logically combining optional value with non-optional value yields optional boolean.
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(sqlpp::compat::make_optional(bar.boolNn) and true)>,
-                             sqlpp::compat::optional<sqlpp::boolean>>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(sqlpp::compat::make_optional(bar.boolNn) or true)>,
-                             sqlpp::compat::optional<sqlpp::boolean>>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(sqlpp::compat::make_optional(bar.boolNn) and
-                                                             sqlpp::compat::make_optional(true))>,
-                             sqlpp::compat::optional<sqlpp::boolean>>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(sqlpp::compat::make_optional(bar.boolNn) or
-                                                             sqlpp::compat::make_optional(true))>,
-                             sqlpp::compat::optional<sqlpp::boolean>>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(bar.boolNn and sqlpp::compat::make_optional(true))>,
-                             sqlpp::compat::optional<sqlpp::boolean>>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(bar.boolNn or sqlpp::compat::make_optional(true))>,
-                             sqlpp::compat::optional<sqlpp::boolean>>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(not sqlpp::compat::make_optional(bar.boolNn))>,
-                             sqlpp::compat::optional<sqlpp::boolean>>::value,
-                "");
-
-  // Logically combining non-optional value with non-optional value yields non-optional boolean.
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(bar.boolNn and true)>,
-                             sqlpp::boolean>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(bar.boolNn or true)>,
-                             sqlpp::boolean>::value,
-                "");
-  static_assert(std::is_same<sqlpp::value_type_of_t<decltype(not bar.boolNn)>,
-                             sqlpp::boolean>::value,
-                "");
+  // time_of_day
+  test_result_row<std::chrono::microseconds>(std::chrono::microseconds{});
 
   // Arithmetically combining optional value with non-optional value yields optional boolean.
   static_assert(std::is_same<sqlpp::value_type_of_t<decltype(sqlpp::value(sqlpp::compat::make_optional(7)) + 8)>,
@@ -282,6 +162,7 @@ int main()
                              sqlpp::compat::optional<sqlpp::boolean>>::value,
                 "");
 
+  // in expression
   static_assert(std::is_same<sqlpp::value_type_of_t<decltype(in(sqlpp::value(7), sqlpp::compat::make_optional(7), 8, 9))>,
                              sqlpp::compat::optional<sqlpp::boolean>>::value,
                 "");
diff --git a/tests/core/types/value.cpp b/tests/core/types/value.cpp
new file mode 100644
index 00000000..3e9a6321
--- /dev/null
+++ b/tests/core/types/value.cpp
@@ -0,0 +1,113 @@
+/*
+ * Copyright (c) 2016-2016, 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 "MockDb.h"
+#include "Sample.h"
+#include <sqlpp11/sqlpp11.h>
+
+namespace
+{
+  auto db = MockDb{};
+}
+
+SQLPP_ALIAS_PROVIDER(r_not_null);
+SQLPP_ALIAS_PROVIDER(r_maybe_null);
+SQLPP_ALIAS_PROVIDER(r_opt_not_null);
+SQLPP_ALIAS_PROVIDER(r_opt_maybe_null);
+
+template <typename T, typename ValueType>
+using is_value_type = std::is_same<sqlpp::value_type_of_t<T>, ValueType>;
+
+template<typename Value>
+void test_value(Value v)
+{
+  using ValueType = sqlpp::value_type_of_t<Value>;
+  using OptValueType = sqlpp::compat::optional<ValueType>;
+
+  auto v_not_null= sqlpp::value(v);
+  auto v_maybe_null= sqlpp::value(sqlpp::compat::make_optional(v));
+  auto v_not_null_alias = sqlpp::value(v).as(r_not_null);
+  auto v_maybe_null_alias = sqlpp::value(sqlpp::compat::make_optional(v)).as(r_maybe_null);
+  auto v_opt_not_null_alias = sqlpp::value(v).as(r_opt_not_null).if_(true);
+  auto v_opt_maybe_null_alias = sqlpp::value(sqlpp::compat::make_optional(v)).as(r_opt_maybe_null).if_(true);
+
+  static_assert(is_value_type<decltype(v_not_null), ValueType>::value, "");
+  static_assert(is_value_type<decltype(v_maybe_null), OptValueType>::value, "");
+  static_assert(is_value_type<decltype(v_not_null_alias), ValueType>::value, "");
+  static_assert(is_value_type<decltype(v_maybe_null_alias), OptValueType>::value, "");
+  static_assert(is_value_type<decltype(v_opt_not_null_alias), OptValueType>::value, "");
+  static_assert(is_value_type<decltype(v_opt_maybe_null_alias), OptValueType>::value, "");
+
+  static_assert(not sqlpp::can_be_null<decltype(v_not_null)>::value, "");
+  static_assert(sqlpp::can_be_null<decltype(v_maybe_null)>::value, "");
+  static_assert(not sqlpp::can_be_null<decltype(v_not_null_alias)>::value, "");
+  static_assert(sqlpp::can_be_null<decltype(v_maybe_null_alias)>::value, "");
+  static_assert(sqlpp::can_be_null<decltype(v_opt_not_null_alias)>::value, "");
+  static_assert(sqlpp::can_be_null<decltype(v_opt_maybe_null_alias)>::value, "");
+}
+
+int main()
+{
+  // boolean
+  test_value(bool{true});
+
+  // integral
+  test_value(int8_t{7});
+  test_value(int16_t{7});
+  test_value(int32_t{7});
+  test_value(int64_t{7});
+
+  // unsigned integral
+  test_value(uint8_t{7});
+  test_value(uint16_t{7});
+  test_value(uint32_t{7});
+  test_value(uint64_t{7});
+
+  // floating point
+  test_value(float{7.7});
+  test_value(double{7.7});
+
+  // text
+  test_value('7');
+  test_value("seven");
+  test_value(std::string("seven"));
+  test_value(sqlpp::compat::string_view("seven"));
+
+  // blob
+  test_value(std::vector<uint8_t>{});
+
+  // date
+  test_value(::sqlpp::chrono::day_point{});
+
+  // timestamp
+  test_value(::sqlpp::chrono::microsecond_point{});
+  using minute_point = std::chrono::time_point<std::chrono::system_clock, std::chrono::minutes>;
+  test_value(minute_point{});
+
+  // time_of_day
+  test_value(std::chrono::microseconds{});
+
+}
+