Question

Suppose I have a table like this:

id     col1     col2     col3
1      a        1        k1
2      a        2        k2
3      a        -3       k3
4      b        3        k4

Now, I want the total of column ‘col2’ for all rows where ‘col1’ is the same as ‘col1’ in the row where ‘id’ = 1.

So that would be 1+2-3=0.

How would I express this in SQL?

Answer 1

SELECT SUM(col2) from TABLE
where col1 in (SELECT col1 from TABLE where id = 1)