added query helper macro and join query parts

demo/main.cpp

@@ -6,6 +6,9 @@
 
 #include "matador/utils/access.hpp"
 
+#include "query_helper.hpp"
+
+#include <iostream>
 #include <string>
 
 struct author
@@ -46,26 +49,36 @@ struct book
   }
 };
 
+QUERY_HELPER(author, id, first_name, last_name, date_of_birth, year_of_birth, distinguished)
+QUERY_HELPER(book, id, book_author, title, published_in)
+
 int main()
 {
   using namespace matador::sql;
+
   const std::string env_var{"MATADOR_BACKENDS_PATH"};
 
   std::string dns{"sqlite://demo.db"};
 //  std::string dns{"memory://test"};
   auto s = std::make_shared<schema>();
+  s->attach<author>("authors");
+  s->attach<book>("books");
+
   connection c(dns, s);
 
   auto books = c.query()
-    .select<book>({"author.name"})
-    .from("book")
-    .join_left("author")
+    .select<book>({qh::book.id.name})
+    .from({"book"})
+    .join_left({"authors"})
     .on("book.author_id"_col == "author.id"_col)
     .where("book.published_in"_col < 2008 && "author.name"_col == "Michael Crichton")
     .order_by("book.title").asc()
     .offset(2)
     .limit(5)
-    .fetch_all<book>();
+    .str();
+//    .fetch_all<book>();
+
+  std::cout << "SQL: " << books << "\n";
 
   // SELECT book.title, book.id, book.author_id, book.published_in, author.name
   // FROM book