Re: xpath() subquery for empty array - Mailing list pgsql-general

On Sun, Jul 12, 2009 at 09:49:15PM +0100, Roy Walter wrote:
> Where exactly does that fit in terms of my original query, i.e.:
>
>    SELECT x
>    FROM (SELECT xpath('//entry[contains(p, ''searchtext'')]/@*', docxml)
>    AS x FROM docs) AS y WHERE x <> [test for empty array?????????]

Something like the following should do the right thing:

  SELECT x FROM (
    SELECT xpath('//entry[contains(p, ''searchtext'')]/@*', docxml) AS x
    FROM docs) AS y
  WHERE array_upper(x, 1) > 0;

--
  Sam  http://samason.me.uk/