Re: Identifying obsolete values

On Wed, 17 Oct 2001 17:17:44 METDST
Haller Christoph wrote:

> I use the second table to identify the actual resp. obsolete ones within the first table.
>
> DELETE FROM advncd_tempreftime;
> INSERT INTO advncd_tempreftime
> SELECT timepoint,mid,lid,sid,MAX(entrancetime) FROM advncd_onfvalue
> GROUP BY timepoint,mid,lid,sid ;
>
> SELECT o.sid,o.timepoint,o.lid,o.mid,o.value FROM advncd_onfvalue o
> WHERE EXISTS
> (SELECT * FROM advncd_tempreftime t WHERE
> o.timepoint = t.timepoint AND
> o.mid = t.mid AND
> o.lid = t.lid AND
> o.sid = t.sid AND
> o.entrancetime = t.entrancetime
> ) ;

Hi,

It seems that a series of the operations can be unified.

SELECT o.sid,o.timepoint,o.lid,o.mid,o.value
FROM advncd_onfvalue as o
WHERE EXISTS
(SELECT t.timepoint, t.mid, t.lid, t.sid
FROM advncd_onfvalue as t
GROUP BY t.timepoint, t.mid, t.lid, t.sid
HAVING o.timepoint = t.timepoint AND
o.mid = t.mid AND
o.lid = t.lid AND
o.sid = t.sid AND
o.entrancetime = MAX(t.entrancetime)
)
;

By the way, a mail server have been downed ?

Regards,
Masaru Sugawara