Re: way to custom sort column by fixed strings, then by field's content

[Susan Cassidy <susan.cassidy@xxxxxxxxxxxxxxxxxxxxxxxx>]

    description    | description
-------------------+-------------
 18 cm long wrench | Scene 1
 absolute root     |
 blue screwdriver  | Scene 1
 red toolbox       | Scene 1
 root 3            | Scene 1
 root 4            | Scene 2
 root 6            | Scene 3
 small wrench      | Scene 1
 tire              | Scene 2

On Mon, Feb 3, 2014 at 11:14 AM, Adrian Klaver <adrian.klaver@xxxxxxxxx> wrote:

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@xxxxxxxxx