Re: ERROR: for SELECT DISTINCT, ORDER BY expressions must

[Bricklen Anderson <banderson@xxxxxxxxxxxx>]

sergey kapustin wrote:
> Hi all!
> can anybody say me what's wrong with this query. I just try to take
> unique values from table column and print them in random order
>
> select distinct num from (select 1 as num union select 2 as num union
> select 1 as num union select 3) t order by random();
> ERROR:  for SELECT DISTINCT, ORDER BY expressions must appear in select 
> list
>
> thank you


select num from
    (select distinct num
    from (select 1 as num union select 2 as num union select 1 as num 
union select 3 as num) a) t
order by random();