[postgis-users] DELETE old lines in a table

[Daniel Grum]

Hi all,

I've a problem with deleting old infos in a table.
I want put information into a table via "insert into" and delte the old 
information that was saved in the tabele befor.
In adition to the "gid" column I have a column, called  
"zeitstempel"(timestamp), that shows me what info is old and what is the 
latest infos.

Here is the sql:

INSERT INTO abbauholz
SELECT nextval('serial') AS GID,
       pt.name AS name,
       ST_Intersection(poly.the_geom,ST_Expand(pt.the_geom, 2000)) AS 
the_geom,
       Area(ST_Intersection(poly.the_geom,ST_Expand(pt.the_geom, 2000))) 
AS flaeche,
       Sum(Area(ST_Intersection(poly.the_geom,ST_Expand(pt.the_geom, 
2000)))) AS sum_flaeche,
       CURRENT_TIMESTAMP AS zeitstempel
FROM public.wald_by poly, public.holzfaeller pt
WHERE poly.the_geom && ST_Expand(pt.the_geom, 2000)
GROUP BY pt.name, poly.the_geom, pt.the_geom;
DELETE FROM abbauholz WHERE date_part('second',zeitstempel) < 
date_part('second', CURRENT_TIMESTAMP);

the last line is the most important, because here came DELETE order.
But it doesn't work, the old info(old lines) stay in the table after the 
sql order.

Can someone help me?

--daniel