Okay, I'm a nimrod.

After putting all this up on a whiteboard to help me think it through, it occured to me that this is in fact a classic overlapping dates...

Rob,

Thanks so much!  That was a lot of work on my behalf!  I will be running this shortly, and then comparing it to my live data to see what comes...

Rob,

I appreciate the post, but I'm afraid your answer is a bit too broad and conceptual for me to get much mileage from.  You say "you can have a function...

john,

multi-part solutions are fine.  I'm an enthusiast for declaring table variables as I go and manipulating my data in stages.  No need for one big honking single-stage rocket, if you...

rockmoose, thanks for sharing the wealth!  You saved my own thinning pate from horrible fate...

And folks -- for the record, apparently this behavior that rockmoose pointed out is also true...

rockmoose,

Well, I can unlearn what I've learnt but I can't unburn what I've burnt...which is several hours of futzing around trying to figure out the cause of this problem, BUT...

You are...

Gary,

Thanks, but I'm confident my code is good.  I didn't list it all here, but I'm using well-tested routines that our team uses all the time.  And as I said,...

And...

I tried to open it with an ADO Command object, but that didnt help...

I tried to issue a set rs = rs.NextRecordset, but no better...

- Tom

Further clues...

It doesn't seem to be a temp-table issue.  If I save the data to a physical table rather than to a temp table, the same problem occurs. 

Weird...

The main features I'm adding are the ability to save common sql statements that you would use to generate your list of dbs.  For instance:

"All Client DBs"...

Scott,

Thanks, great.  Actually, that somewhat confirms my own analysis of the situation...and reasonably well describes the "home-grown tool" that I've built and am using.  It's VB, with the SQL-DMO objects,...

Thanks, Andrew -

Good idea, using newid() to generate a unique name.  That's a nice solution, and I may use it elsewhere but it's a solution to a problem rather secondary...

Rockmoose and John Hanson,

Thanks, all.  As it turned out I found I could make the SP work by using the dynamic field-name generation technique.  The one part about it that's...

Razvan,

Yes, thanks -- it's a matter of Identity columns, not primary keys.  And yes, of course, because identity columns are involved I'd need to use SET_IDENTITY_INSERT ON/OFF, -- but that doesn't...

D'oh!  Right, of course!  Thanks...

Yeah, that works much better!

- Tom