PostgreSQL - conditional ordering

Question

I have the following table:

key | date         | flag
--------------------------
1    now()           true
2    now() - 1 hour  true
3    now() + 1 hour  tru         


        

Answer 1

conditional order can be performed with CASE, like here:

select *
    from test
order by 
    flag
  , case when flag then date end desc
  , case when not flag then date end asc