Comment by snidane

You don't need additional SQL repetitive cruft.

      from population
    select country, rollup(city), count(*)
      sort

Can represent this repetitive SQL query:

    select country, city, count(*)
      from population
     group by country, rollup(city)
     order by country, city

Information in group by is often redundant. You can tell which columns are measures vs dimensions by examining the 'aggregate' function - rollup or no function vs sum, count, avg. Order by can have a default to sort by all columns instead of naming them one by one.