At 11:08 AM 23-08-02 -0300, you wrote:

>My question:
>Why would the DISTINCT restriction affect the usage of a subselect?

I hoped you wouldn't ask that! I would have explained it if I could
remember it. I've seen an explanation somewhere by Ann or Diane (probably
around 1997-8 vintage) that made sense to me at the time...it has to do
with the way the engine holds duplicate groups of interim results for
comparing in order to establish distinctness.

You could try querying the mers archive for postings by Ann (Harrison) or
Diane (Brown) with the keyword DISTINCT...I know it's there somewhere.

heLen