On Thu, Nov 09, 2006 at 04:37:23PM +0100, Alban Hertroys wrote:
> 'lo list,
> 
> I have a plpgsql SP where I loop through a cursor. I have an internal 
> variable that keeps the previous row, so that I can compare it with the 
> current row in the cursor.
> Like so;
> 
> DECLARE
>     current table%ROWTYPE;
>     previous table%ROWTYPE;
> BEGIN
>     LOOP
>       FETCH tableCur INTO current;
> 
>       -- Do stuff
> 
> But, in this loop I need to compare the previous row to the current one. 
> To do that I need to know whether a row was assigned to 'previous', or 
> there'll be very little to compare (if it doesn't throw an error).
> How do I check for that?
> 
> I guess it would be like this, but I'd like to be sure.
> 
>       IF previous IS NOT NULL
>       THEN
>               -- Compare previous and current column values
>       END IF
> 
>       previous := current;
>     END LOOP;
> END;

Try it and see. :) I think that will work.

Might be better to just capture the error.
-- 
Jim Nasby                                            [EMAIL PROTECTED]
EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)

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