Nice work, Mark.

A couple of points, though. First, the word "variance" is frequently misused when people mean to say "variation". This can cause ambiguity in math/stats where "variance" is defined...

Whatever governments do (or promise to do), there needs to be an outside body -- preferably modelled on the Open Source community -- that polices the police, as it were....

Thanks.

Is it normally necessary, or just good practice?

Stephen,

Your SQl code worked like a charm. Thanks a zillion!

Thankyou very much, Stephen.

I have barely started testing (got sidetracked by the need to start documenting big-time), but it looks like it works!

Sounds good, Stephen. But I'm still stuck on the 1st step of your plan: "... filter them for parts that only appear in the parts list I want". In my 1st example,...