removed class query and moved their static methods to simple functions

demo/main.cpp

@@ -190,7 +190,7 @@ int main() {
   mc.date_of_birth = "19.8.1954";
   mc.year_of_birth = 1954;
   mc.distinguished = true;
-  auto insert_authors_sql = query::insert()
+  auto insert_authors_sql = insert()
     .into(AUTHOR)
     .values(mc)
     .execute(*c);
@@ -201,7 +201,7 @@ int main() {
     return 0;
   }
 
-  auto authors_result = query::select(AUTHOR)
+  auto authors_result = select(AUTHOR)
     .from(AUTHOR)
     .fetch_all(*c);
 
@@ -243,8 +243,8 @@ int main() {
   //  .values( {3, "Misery", mc.id, 1984} )
   //  .execute();
   //
-  // auto select_books_sql = query::select( BOOK, {AUTHOR.last_name} )
-  auto select_books_sql = query::select({BOOK.id, BOOK.title, BOOK.author_id, BOOK.published_in, AUTHOR.last_name})
+  // auto select_books_sql = select( BOOK, {AUTHOR.last_name} )
+  auto select_books_sql = select({BOOK.id, BOOK.title, BOOK.author_id, BOOK.published_in, AUTHOR.last_name})
     .from(BOOK)
     .join_left(AUTHOR)
     .on(BOOK.author_id == AUTHOR.id)
@@ -288,17 +288,17 @@ int main() {
   //
   // std::cout << "SQL: " << drop_authors_sql << "\n";
   //
-  auto res = query::select({PAYLOAD.id})
+  auto res = select({PAYLOAD.id})
     .from(PAYLOAD)
     .join_left(JOB)
     .on(JOB.payload == PAYLOAD.id)
     .where(
-      in(PAYLOAD.id, query::select({JOB.state})
+      in(PAYLOAD.id, select({JOB.state})
          .from(JOB)
-         .where(JOB.state == job::job_state::Running).compile(c->dialect())
+         .where(JOB.state == job::job_state::Running)
       ) &&
-      in(PAYLOAD.id, query::select({TEMPORARY_TABLE.id})
-         .from(TEMPORARY_TABLE).compile(c->dialect())
+      in(PAYLOAD.id, select({TEMPORARY_TABLE.id})
+         .from(TEMPORARY_TABLE)
       )
     ).compile(c->dialect());
   // // .fetch_value<unsigned long>();