I'm trying to create an inquiry tool that is simple enough for managers
to use. Through check boxes I know what tables and fields he wants to
see, sums, averages, etc. From this I can construct the GROUP BY clause
and the ORDER BY clause. I have structured DDL.

I do not have the algorithm to construct the WHERE clause that ties
multiple tables together. It seems to involve an abstract network, with
nodes=tables and directedlinks=foreignkeys. Perhaps a path, perhaps a
spanning tree, is needed. The difficulty can be seen when the tables
are not directly linked. Can you give me a URL of something that will
help me?

For example, the SQL statement might look like this:
SELECT STATE.NAME, SUM( EMPLOYEE.INCOME )
FROM ...
WHERE ...
GROUP BY STATE.NAME
ORDER BY STATE.NAME

For a given DDL the WHERE clause might have to be
WHERE EMPLOYEE.NAME = PERSON.NAME
AND PERSON.STATECODE = STATE.STATECODE

In this example, the tables EMPLOYEE and STATE are not directly linked
together, but can be tied together through an intermediate table
PERSON. Given the SELECT clause, how to find the intermediate table(s)
through which the connections must be made? I can come up with rules
that *seem* to work, but I do not understand the theory well enough to
have confidance in my technique.

Thank you.