Question

I have two tables: tableA and tableB. How can I get all the records that are in tableA but not in tableB? I am interested in the proper way to do this, not workarounds. I’ve tried using a left join and then adding where ID is not null. It works, but I am not sure whether that is the right way to do it.

Answer 1

select * from tableA
where id not in (select id from tableB)

or

select * from tableA a
left join tableB b on a.id = b.id
where b.id is null

Both are totally acceptable ways to retrieve what you asked.