How an I get TestComplete to recognize "is null" in a DB query?

I am trying to use a DB variable to pull some data to use for testing, but TestComplete doesn't seem able to recognize the "is null" keyword.  My query is in the form of:

SELECT
field1,
field2,
field3,
field4
FROM
table
WHERE
field5 = somevalue and field6 = anothervalue and field7 is null

When I test the query in TestComplete, it pulls back data, but the data is wrong.  It is recognizing everything but the "is null" part of the query.  The query works fine if I log into the db admin tool and gets the desired result, but it won't work in TestComplete.  Is there something I'm missing?