I have this union query (below) that joins two tables. However, when I create
a new query with the union query as it's source, I do a sum on the [Bill
Amount] with a Group By on [Vendor], expecting to get a total on bill amount
with 1 vendor and all the rest should roll up to a second record because
vendor is otherwise blank. However I end up getting an extra record (total of
3).

Based on this union query structure can you give me some ideas of why that
would be?

SELECT Code, ProjNo,  F3, Invoice, TT, LLT, MidTask, TASK_NAME, [Empl],
[PER_DIEM_CODE] as [Per Diem Code], Classification, [Class Grade], [Title],
[Job Title Override], Hours, [Bill Rate],[Raw Cost], 0 as Quantity,  [Bill
Amount], ExpDate, "" as  [ExpCat], [ExpType], "" as Vendor,  "" as VIN, Thru
FROM [Labor-Current]

UNION ALL SELECT Code,ProjNo, F3,Invoice,TT, LLT, MidTask, "" as TASK_NAME,
[Empl],"" as [Per Diem Code], "" as Classification,"" as [Class Grade], "" as
[Title], "" as [Job Title Override], null as  Hours, [Bill Rate], null as
[Raw Cost], Quantity, [Bill Amount],ExpDate,[ExpCat],[ExpType], Vendor, VIN,
Thru
FROM [Expense-Current];