UPDATE table .....

[Maik Trömel <maik.troemel@xxxxxxxxxx>]

/Hi,

I want to update a column (integer). The value that should be set is the 
sum of the column I want to update and an integer column from another 
table with similiar information an the same primary key "gid".

It should work this way:

Table1            +           Table2           =        Updated Table1
gid   var228//                 gid   var228//               gid    var228/
/1      1                           1      3                        1   
    4
2      2                           2      2                        2   
    4
3      1                           3      7                        3   
    8


I tried some insturctions like:

UPDATE
   geom_summen
SET
   var228=( SELECT
                       (geom_summen.var228 + geom_ns_wrf.var228)
                   FROM
                       geom_summen, geom_ns_wrf
                   WHERE
                       geom_summen.gid=geom_ns_wrf.gid )
WHERE
   geom_summen.gid=geom_ns_wrf.gid;

But all of them don't work.
I know it can't be very difficult. But I can't get the solution. 
Probably someone can help me.

Thank for help!

Maik
/