Listing 1: UNION ALL Alternative to GROUP BY ALL

SELECT City, COUNT(*) AS NumEmps
FROM dbo.Employees
WHERE HireDate >= '19930101'
GROUP BY City

UNION ALL

SELECT DISTINCT City, 0 AS NumEmps
FROM dbo.Employees AS E1
WHERE NOT EXISTS
  (SELECT *
   FROM dbo.Employees AS E2
   WHERE E2.City = E1.City
     AND HireDate >= '19930101');