Question

Assuming the following table:

USER  COLOR  ORDER
==================
JOE   RED    1
JOE   BLUE   2 
PHIL  BLUE   3

Joe first chose red, then chose blue as his favorite color… How do you write a query that returns:

COLOR COUNT
RED   1
BLUE  1

Where only Joe’s first vote is counted?

Answer 1

You would get the lowest ORDER value for each USER, and then join that against the table again to get the COLOR for those records, then group by the COLOR to count them:

select y.COLOR, count(*) as COUNT
from (select USER, min(ORDER) as ORDER from TheTable group by USER) x
inner join TheTable y on x.USER = y.USER and x.ORDER = y.ORDER
group by COLOR