Re: Count of records in a row - Mailing list pgsql-general

On 10/22/13, Rémi Cura <remi.cura@gmail.com> wrote:
> But it is immensely easier and sometimes mandatory to use instead
> a plpgsql function using cursor (or cursors).
>
> It would be something like that in plpgsql :
>
> cursor on table of letter ordered
> accum = 0;
> loop on rows of table ordered
>
> if letter = previous letter, new_id = accum
> else accum ++ ; new_id = accum
>
> old letter = new_letter
> new letter = next letter;
>
> end of loop,

Shouldn't it be possible to do that with a FOR loop without a cursor?

It might be that procedural is the way to go.  But I still believe
that relational algebra can handle this, even without a window
function.  Something like:

SELECT event e, COUNT(
    SELECT event oe ... WHERE oe.event_time > e.event_time AND NOT EXISTS (
             SELECT event te WHERE te.event_time > e.event_time AND
te.event_time < oe.event_time))

.