How to use MAX() on a subquery result?

Question

I am new to Oracle and the SQL world. I have a slight issue with a query that I cannot figure out for the life of me, I have spent a few hours trying different approaches and I

Answer 1

This is all good SQL.

The best way to find a column value using the max primary key column value is:

SELECT .... from tablename
WHERE ... AND
  (SELECT max(primary key name) FROM tablename WHERE .... ) = primary_key_name

this example will return a scalar value.