Excel has a cell formula called Product() that can operate on a list
of varying size.  Basically I'm looking for the equivalent for an
Access query.  I haven't found anything, and it seems like such a
simple function.

Something along the lines of:
SELECT ValueTable.lineid, Sum(ValueTable.value) AS SumOfvalue
FROM ValueTable
GROUP BY ValueTable.lineid;
... except, instead of Sum() it'd be some elusive Product() function
that I can't find.

Thanks --