diff --git a/include/sqlpp11/consistent.h b/include/sqlpp11/consistent.h
index e55c20c8..ad80609e 100644
--- a/include/sqlpp11/consistent.h
+++ b/include/sqlpp11/consistent.h
@@ -33,8 +33,9 @@ namespace sqlpp
   struct consistent_t : std::true_type
   {
     template <typename... T>
-    static constexpr void verify(T&&...)
+    static constexpr int verify(T&&...)
     {
+      return 0;
     }
   };
 }  // namespace sqlpp
diff --git a/include/sqlpp11/data_types/text/data_type.h b/include/sqlpp11/data_types/text/data_type.h
index 6504b23c..3b72ed73 100644
--- a/include/sqlpp11/data_types/text/data_type.h
+++ b/include/sqlpp11/data_types/text/data_type.h
@@ -26,6 +26,8 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <string>
+
 #include <sqlpp11/type_traits.h>
 
 namespace sqlpp
diff --git a/include/sqlpp11/mysql/connection.h b/include/sqlpp11/mysql/connection.h
index a75945e7..fbfdb79f 100644
--- a/include/sqlpp11/mysql/connection.h
+++ b/include/sqlpp11/mysql/connection.h
@@ -39,7 +39,6 @@
 #include <sqlpp11/mysql/update.h>
 #include <sqlpp11/serialize.h>
 #include <iostream>
-#include <sstream>
 #include <string>
 
 namespace sqlpp
@@ -281,7 +280,10 @@ namespace sqlpp
         return serialize(t, context);
       }
 
-      [[deprecated("Use ping_server() instead")]] bool is_valid() const
+#if SQLPP_CXX_STD >= 201402L
+      [[deprecated("Use ping_server() instead")]]
+#endif
+      bool is_valid() const
       {
         return _handle->ping_server();
       }
diff --git a/include/sqlpp11/portable_static_assert.h b/include/sqlpp11/portable_static_assert.h
index 7129aff1..3271bf36 100644
--- a/include/sqlpp11/portable_static_assert.h
+++ b/include/sqlpp11/portable_static_assert.h
@@ -40,9 +40,10 @@ namespace sqlpp
       static_assert(wrong_t<T...>::value, message); \
     }                                               \
     template <typename... T>                        \
-    static constexpr void verify(T&&...)                 \
+    static constexpr int verify(T&&...)             \
     {                                               \
       static_assert(wrong_t<T...>::value, message); \
+      return 0;                                     \
     }                                               \
     auto begin() const -> void;                     \
     auto end() const -> void;                       \
diff --git a/include/sqlpp11/result_row.h b/include/sqlpp11/result_row.h
index a6241b62..8bb64d5f 100644
--- a/include/sqlpp11/result_row.h
+++ b/include/sqlpp11/result_row.h
@@ -314,6 +314,7 @@ namespace sqlpp
       _impl::_apply(callable);
 
       std::size_t index = sizeof...(FieldSpecs);
+      std::ignore = index; // silence warnings in case _dynamic_field_names is empty
       for (const auto& field_name : _dynamic_field_names)
       {
         _dynamic_fields.at(field_name)._apply(callable);
@@ -327,6 +328,7 @@ namespace sqlpp
       _impl::_apply(callable);
 
       std::size_t index = sizeof...(FieldSpecs);
+      std::ignore = index; // silence warnings in case _dynamic_field_names is empty
       for (const auto& field_name : _dynamic_field_names)
       {
         _dynamic_fields.at(field_name)._apply(callable);