session queries as statement progress

include/matador/sql/query_result.hpp

@@ -139,7 +139,7 @@ public:
   , creator_(std::move(creator)) {}
 
   iterator begin() { return std::move(++iterator(this)); }
-  static iterator end() { return {}; }
+  iterator end() { return {}; }
 
 private:
   friend class query_result_iterator<Type>;