Which territory has the greatest difference in sales from previous year to this year? Indicate the difference, as well as the name and country of the region.
greatest difference in sales from previous year to this year refers to Max(Subtract(SalesLastYear,SalesYTD));
SELECT SalesLastYear - SalesYTD, Name, CountryRegionCode FROM SalesTerritory ORDER BY SalesLastYear - SalesYTD DESC LIMIT 1