Question

Just need some quick clarification

I have 2 Queries in my Access Database that should return Inverse results:

SELECT Equipment.title
FROM Equipment
WHERE (((Equipment.[EquipmentID]) Not In (

    select EquipmentID
    from DownPeriod
    where UpDate is null
)));

The 2nd just excludes the Not before the In.
My Confusion comes from the fact that the query posted above does not return any results if an EquipmentID field has at least 1 null value in the DownPeriod table.

It works fine if the fields are filled, and the inverse query list always works. This makes me think there’s an issue with the null value.

Now this field should never be null but I wanted to know if I could still get this to work in the unlikely event a null did occur.

Thank you in advanced!

Answer 1

Try joins:

SELECT Equipment.title FROM Equipment INNER JOIN DownPeriod
ON Equipment.EquipmentID = DownPeriod.EquipmentID
WHERE DownPeriod.UpDate is null

and

SELECT Equipment.title FROM Equipment INNER JOIN DownPeriod
ON Equipment.EquipmentID = DownPeriod.EquipmentID
WHERE DownPeriod.UpDate is not null

See if a change in syntax fixes your issue.

Not only should this work, but I believe it is a faster practise than using the IN() NOT IN() methods (might be wrong on that, but it looks nicer to read). It also adds the ability to quickly change the “is not null” criteria just the same as IN->NOT IN