I just wanted to issue a blanket "thanks" to all who responded to my
inquiry about what to do about 'unique'. Distinct is the equivalent
aggregate function as many pointed out. A co-worker said that Oracles
'unique' is probably an optimized version of distinct that takes
advantage of some Oracle specific indexing.
The example that I used to illustrate my problem in the first place was
seriously flawed as many pointed out. The PostgreSQL db had been
created from a Fastreader control file that had all column names in
double quotes, ex. "total" instead of total; This produced a normal
looking DB that did not react correctly to any SQL that used a column
name. So for example, select count(*) would return the correct row
count but count(some_column) would produce a 'no such column error'.
My difficulty with unique was mostly caused by the failure of every
attempt to come up with an alternate query which was caused, in turn,
by the columns names used to create the tables.
All in all, a pretty revolting experience with one possible bright
spot, I think I have proved a little known principle of computer
science: "garbage in, garbage out".
Many thanks to all who took the time to reply,
-=bill