Sum of the most recent non-null columns (window function with “ignore nulls”)

Question

I am using PostgreSQL 9.1.9.

In the project I am working on, some most recent records have null columns because that information was not available when that row was crea

Answer 1

Is this what you are trying to describe?

SELECT sum(col1), sum(col2), sum(col3) FROM table2 WHERE col1 IS NOT NULL

(although I omitted the join on table1; that is an exercise for the reader)