# 1398 Using a NOT Operator With an OR Expression From Two Different Data Sources Causes Incorrect Results

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I'm running v3.21 and I'm getting what seem to be some strange results when using NOT's in my where clause.

For example, I run this query:

SELECT c.FirstName, c.LastName, d.DonationDate, d.Amount
FROM Contacts c
LEFT OUTER JOIN Donations d ON (c.ContactID=d.ContactID)
WHERE ( NOT
(c.FirstName <= 'M') and
NOT (d.DonationDate between '1998-07-22' and '2003-07-22')
)

and I get a list of 280 records where the firstname is not <= 'M' and where the donation date is outside the range of 7/22/98 to 7/22/03.

But if I run what should be the equivalent query:

SELECT c.FirstName, c.LastName, d.DonationDate, d.Amount
FROM Contacts c
LEFT OUTER JOIN Donations d ON (c.ContactID=d.ContactID)
WHERE NOT (
(c.FirstName <= 'M') OR
(d.DonationDate between '1998-07-22' and '2003-07-22')
)

from this query I get 575 records which include, among other things, records where the first names are definitely <= 'M' and where the dates are between 1998 and 2003. I'm not sure exactly what records are included and what are excluded, but the full record set (without a WHERE restriction) has 855 records, so something is getting excluded.