I don't really understand Except very well.
This statement, when run using huge tables is very slow. I think I should be using Except instead.
Select ssn, name, address from PeopleTable1
ssn not in (Select ssn from PeopleTable2 where year = '2020')
When I try using Except, I get an error saying that both Select statements have to have the same number of items listed. But in this case they don't. I just want to do what's shown above.