Reason for - ORDER BY items must appear in the select list if SELECT DISTINCT is specified

Question

I know that the query below causes the error - ORDER BY items must appear in the select list if SELECT DISTINCT is specified.

SELECT DISTINCT city
FROM HR.Em         


        

Answer 1

try this: 
select city 
    from (
    SELECT city, min(birthdate) as birthdate
    FROM HR.Employees
    WHERE country = N'USA' AND region = N'WA'
    group by city
          ) as t
    order by birthdate