select not in not working

[#1]

Hi all,

I am trying to get a list of IDs from a source while excluding a few select subjects.

so here are the queries:

select count(distinct idvar) from db1.source;

144252637

select count(distinct idvar) from db1.source where idvar in (select distinct idvar from db2.list);

710610

select count(distinct idvar) from db1.source where idvar not in (select distinct idvar from db2.list);

0

Please excuse the formatting in this message.  Something is not adding up here.  I would like some help please.

Thanks!