poging 2. first step writing query
poging 2. second step writing query
poging 3. third step writing query
poging 2. (vorige commit poging 3 moet poging 2 zijn). first step rewriting query. The shunting rule is used
poging 2. second step rewriting query. The shunting rule is used.
poging 2. third step rewriting query. The shunting rule is used.