Not sure about cMax - don't see that in any of the posts. If you look at the queries, the query posted contains a "derived table". This is a subquery that we can join against. (inside the parens). In that derived table, we use an alias to define backup_date (e.g. select getdate() backup_date or select getdate() as backup_date or select backup_date = getdate() )

That's probably where this is coming from. We use this because we don't want every date in the table, just the latest/max date.