UPDATE geom_summen a SET a.var228= a.var228 + (SELECT b.var228 FROM geom_ns_wrf b WHERE b.gid=a.gid); Use Coalesce if you want to substitute zero for null, otherwise the column will be updated to null, if any of the values that was summed was null. On 12/13/05, Maik Trömel <maik.troemel@xxxxxxxxxx> wrote: > /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 > / > > ---------------------------(end of broadcast)--------------------------- > TIP 9: In versions below 8.0, the planner will ignore your desire to > choose an index scan if your joining column's datatypes do not > match > -- Regards Pandu