Your example for a row-oriented just adds UNION. But you need first to order by column to get the rows in the desired order, while SELECT just indicates which

Your example for a row-oriented just adds UNION. But you need first to order by column to get the rows in the desired order, while SELECT just indicates which column from the rows to return. source table -> filtered rowset -> grouped rowset -> filtered grouped rowset -> ordered rows -> ordered rows with selected columns only Source: I was working several years as a Human Query Planner for the columnar DB ;)