Select records based on column priority

Question

First of all, the title of this question is horrible, but I didn\'t find a better way to describe my issue.

There\'s probably a very easy way to do this, but I couldn\'t

Answer 1

I just want to offer that you can do this with a group by:

select (case when sum(case when colour = 'Green' then 1 else 0 end) > 0
             then max(case when colour = 'Green' then id end)
             else max(case when colour = 'Red' then id end)
        end) as id,
       product_id
       (case when sum(case when colour = 'Green' then 1 else 0 end) > 0 then 'Green'
             else 'Red'
        end) as colour
from t
group by product_id