Re: way to custom sort column by fixed strings, then by field's content - Mailing list pgsql-general

On 02/03/2014 10:53 AM, Susan Cassidy wrote:
> I have a column that contains items like
> 'absolute root'
> 'root 3'
> 'root 4'
> 'root 5'
> 'scene 1'
> 'scene 2'
> 'scene 3'
>
> and I would like them to sort in that order.
>
> I tried:
> select sti.description, sc.description from scene_thing_instances sti
> join scenes sc on sti.scene_id = sc.scene_id
>    order by CASE sc.description
>              when (sc.description = 'absolute root'::text) then 1
>              when (sc.description ilike 'root%') then  2
>              else 3
>             END;
>
> I was starting with this, and was going to add perhaps another case
> statement.
>
> But it gives me:
> ERROR:  operator does not exist: text = boolean
> LINE 3:             when (sc.description = 'absolute root'::text) th...
>                      ^
> HINT:  No operator matches the given name and argument type(s). You
> might need to add explicit type casts.
>
> I don't understand this because description is a text column, not
> boolean, and certainly 'absolute root'::text is a text string.
>
> This is 9.2.
>
> Ideas, anyone?

select sti.description, sc.description from scene_thing_instances sti
join scenes sc on sti.scene_id = sc.scene_id
   order by sc.description, CASE
             when (sc.description = 'absolute root'::text) then 1
             when (sc.description ilike 'root%') then  2
             else 3
            END;

>
> Thanks,
> Susan


--
Adrian Klaver
adrian.klaver@gmail.com