Hello Daniel, I am not very sure of your question but
What about the modulo (%) operator ? - "WHERE i%10 = 0" This will keep only rows where the rest of division of i by 10 is 0. e.g. 15 % 10 = 5 KO (15 / 10 = 1 rest 5) 30 % 10 = 0 OK (30 / 10 = 3 rest 0) 23 % 10 = 2 KO (22 / 10 = 2 rest 3) ... Regards, Nicolas Gillet -----Message d'origine----- De : [email protected] [mailto:[email protected]] De la part de Daniel Grum Envoyé : mardi 13 octobre 2009 11:18 À : PostGIS Mailing-List Objet : [postgis-users] Update the geom of a table WHERE "i" is an even number Hi, I need a possibilty that a table "wald_by" will be updatet WHERE my counter "i" is an even number?! UPDATE wald_by SET the_geom = the_geom - ST_Intersection(poly.the_geom,ST_Expand(pt.the_geom, 2000)) FROM public.wald_by poly, public.holzfaeller pt, public.runden i WHERE poly.the_geom && ST_Expand(pt.the_geom, 2000) AND pt.style=2 AND* i/5=2*; i/5=2 ???--> That mean: this UPDATE should be done if i=[10, 20, 30, 40...] !!!! And WHERE "i" is another number nothing should be done-->the_geom=the_geom the_geom is a forest area where forest will be cut, and after 10 rounds the area of the cut down area should be deducted from the original forest area-->the forest will be smaller after 10 rounds! There are two modes of lumberjacks, the one mode(pt.style=1) he cut down the wood regenerative and the other one is clearing the forest completely-->the area should be deducted. "i" will be stored every round in one table: "runden" and every round this SQL will be done: UPDATE runden SET i=i+1; Are there any ideas? --daniel _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
