Hi, Thurstan On Thu, 20 Sep 2001 17:30:46 +0100, "Thurstan R. McDougle" <[EMAIL PROTECTED]> wrote:
> [...] >Carl van Tast had 2 good methods as follows > >SELECT userid, val >FROM tbl >WHERE NOT EXISTS (SELECT * FROM tbl AS t2 > WHERE tbl.userid=t2.userid AND t2.ts > tbl.ts); > >or > >SELECT tbl.userid, tbl.val >FROM tbl > INNER JOIN > (SELECT userid, max(ts) AS maxts > FROM tbl > GROUP BY userid) AS t2 > ON (tbl.userid=t2.userid AND tbl.ts=t2.maxts); ... although I like Tom Lane's even better. This one should outperform all others, especially my first one: > SELECT DISTINCT ON (userid) userid, val, ts FROM table > ORDER BY userid, ts DESC; That's the reason I'm here: learning by helping :-) Kind regards Carl van Tast ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
