Re: Is it possible to get DISTINCT rows from RETURNING clause?

Hey Gnanakumar,

You can wrap you UPDATE query into SQL function returning TABLE, e.g:

CREATE OR REPLACE FUNCTION public.update_mytable()
RETURNS TABLE(email text, column1 text, column2 text, column3 text)
LANGUAGE sql
AS $function$
UPDATE MYTABLE SET ABOOLEANCOLUMN = true FROM MYTEMPTABLE WHERE EMAIL =
MYTEMPTABLE.EMAIL RETURNING EMAIL, COLUMN1, COLUMN2, COLUMN3;
$function$;

Next you can write, e.g:
SELECT DISTINCT * FROM
(SELECT update_mytable()) AS foo(email, column1, column2, column3);

And so on.

2011/2/18 Gnanakumar <gnanam(at)zoniac(dot)com>

> Any ideas?
>
> -----Original Message-----
> From: Gnanakumar [mailto:gnanam(at)zoniac(dot)com]
> Sent: Thursday, February 17, 2011 12:36 PM
> To: pgsql-sql(at)postgresql(dot)org
> Subject: Is it possible to get DISTINCT rows from RETURNING clause?
>
> Hi,
>
> Is it possible to get DISTINCT rows from an UPDATE statement using
> RETURNING
> clause?
>
> "MYTABLE" columns are:
> APRIMARYKEYCOLUMN
> ABOOLEANCOLUMN
> EMAIL
> COLUMN1
> COLUMN2
> COLUMN3
>
> UPDATE using RETURNING clause query:
> UPDATE MYTABLE SET ABOOLEANCOLUMN = true FROM MYTEMPTABLE WHERE EMAIL =
> MYTEMPTABLE.EMAIL RETURNING EMAIL, COLUMN1, COLUMN2, COLUMN3;
>
> Here in this case, I expect to return distinct rows from these columns:
> EMAIL, COLUMN1, COLUMN2, COLUMN3.
>
> I even tried out some ways of getting distinct rows, but it doesn't work.
> Though I can still solve this at application layer, I'm trying to find
> whether this could be controlled at query-level. Any different
> ideas/suggestions are appreciated.
>
> Regards,
> Gnanam
>
>
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--
// Dmitriy.