select query with Not IN keyword

Question

I have two Tables as below..

1. tbPatientEncounter
2. tbVoucher

when i execute select query as below

Select EncounterIDP,EncounterNumber from tbPatientEncounter

it returens me 180 rows. and

Select VoucherIDP,EncounterIDF from tbVoucher

above query returns me 165 rows.

but i want to execute select query that returns me data like EncounterIDP not in tbVoucher, for that i have tried below Select query...

    Select * from tbPatientEncounter pe 
    where pe.EncounterIDP not in 
    (Select v.EncounterIDF from tbVoucher v )

it doesn't returns any row. in first image it shows EncounterIDP 9 in tbPatientEncounter, but it not inserted in tbVoucher for that i have tried select Query like

Select * from tbVoucher where EncounterIDF = 9 

it returns me 0 rows.

My question is what is wrong with my above Not In Query.?

Answer 1

In all likelihood, the problem is NULL values in tbVoucher. Try this:

Select *
from tbPatientEncounter pe 
where pe.EncounterIDP not in (Select v.EncounterIDF
                              from tbVoucher v
                              where v.EncounterIDF is not NULL
                             )

Answer 2

Are you comparing the correct fields in tbVoucher?

Try using a left join

Select EncounterIDP,EncounterNumber from tbPatientEncounter
       left join tbVoucher on EncounterIDP = EncounterIDF
where EncounterIDF is null

Answer 3

Call me a skeptic because I don't see anything wrong with your query. Is this really all in the query or did you simplify it for us?

Select * from tbPatientEncounter pe 
where pe.EncounterIDP not in 
(Select v.EncounterIDF from tbVoucher v )