Amortization Report

I'm creating a financial debt program using SQL 2005 as the back-end and
Access 2007 (*.accdb) as the front end for a few simple forms and reports.
One of the reports they need is an amortization schedule for project debts.
Excel has a function to perform these calculations (PPMT). Does SQL 2005
have any similar functions? It would be ideal to have the values available
in a query. If not, how about Access 2007 reports?

Thanks.

Here is a version of the aggregate product function in SQL so you can
do NPV and other "flow of incomes" functions in Standard SQL. The
idea is that there are three special cases - all positive numbers,one
or more zeros, and some negative numbers in the set.

Within the case where you have negative numbers, there are two sub-
cases: (1) an even number of negatives or (2) an odd number of
negatives. You then need to apply some High School algebra to
determine the sign of the final result.

SELECT CASE MIN (SIGN(nbr))
WHEN 1 THEN EXP(SUM(LN(nbr))) -- all positive numbers
WHEN 0 THEN 0.00 -- some zeroes
WHEN -1 -- some negative numbers
THEN (EXP(SUM(LN(ABS(nbr))))
* (CASE WHEN
MOD (SUM(ABS(SIGN(nbr)-1)/ 2)), 2) = 1
THEN -1.00 ELSE 1.00 END)
ELSE NULL END AS big_pi
FROM Foobar;

SELECT CASE MIN(ABS(SIGN(nbr)))
WHEN 0 THEN 0.00 -- some zeroes
ELSE -- no zeroes
EXP(SUM(LOG(ABS(NULLIF(nbr, 0)))))
* CASE WHEN MOD (CAST(SUM(ABS(SIGN(nbr)-1)/2) AS INTEGER),
2) = 1
THEN -1.00 ELSE 1.00 END
END AS big_pi

But to be honest, you would probably be better of if you built a look-
up table from calculations done with Excel or a financial package
that has more accurate computations for floating points, etc.