newbie-SQL Count

I have a table, there are more columns than this. I used this to keep it simple.

ColA    ColB       Quantity
   30       24               2
   30        0                1

I want to do

UPDATE myTable SET Quantity= (SUM(Decode(ColA,NULL,0,0,0,1) +Decode(ColB,NULL,0,0,0,1) )

I get an error message of :
group function is not allowed here

How can I count each Column that has a POSITIVE number and put the sum in QUANTITY?

TIA
Steve Received on Mon Mar 26 2007 - 16:53:05 CDT