Question

Do both the following queries always give the same results? If not, why not?

1)

select PayFrequencyTypeID, PayFrequencyDesc 
from db_uspaybo.tblpayfrequency 
where (PayFrequencyTypeID,1) not in (
   select payfrequencytype,1 
   from tblcustomerpayapproval 
   where fedtaxid='903008887' and payrollyear=year(curdate())
);

2)

select payfrequencytypeid 
from tblpayfrequency 
where not exists (
  select distinct payfrequencytype 
  from tblcustomerpayapproval
);

Thanks in advance.

Answer 1

I think this is what you want with ‘Not Exists’
A.Id and B.Id here is the Pk and FK that connect these tables.(I don’t know the exact field name)

select payfrequencytypeid from tblpayfrequency A
where not exists ( select *
from tblcustomerpayapproval B where A.Id=B.Id and B.fedtaxid=’903008887′ and B.payrollyear=year(curdate()));