Sum query question

Question

Hey guys, sorry for a newbie question but here goes:
I have a table with col1, col2, col3, col4
where col1,col2 and col3 are values and col4 is the sum of the values.
The problem is that the sum column is currently empty and I was wondering how do I write a query that will add the sum to each row?
Thanks in advance for any help.

Answer 1

Note that the posted solutions assume that col1, col2 and col3 are never null. If any of them could be null, then youe need to use NVL to avoid adding NULL to a number:
SQL> SELECT a, b, c, a + b + c total
  2  FROM (SELECT 1 a, 2 b, 3 c FROM dual UNION ALL
  3       SELECT 1, 2, NULL FROM dual);
         A          B          C      TOTAL
         1          2          3          6
         1          2Also, why do you need to store the sum of columns in the sa,e row. You should just do the adding when you select the records. It would be simple enough to create a view over the base table that does that.
John