John,

This is the idea I got from Al Doman quite recently (search "Comparing two arrays" thread):

You can do it this way:
pseudo-code

lcUniqueTableName=sys(2015) && could not remeber this sys
select FreeTable
copy structure to (m.lcUniqueTableName)
select (m.lcUniqueTableName)
append from FreeTable
append from DBCTable
lcGroupBy=""
lnFields=fcount()
for i=1 to m.lnFields
    lcGroupBy=m.lcGroupBy+field(m.i)+iif(m.i=m.lnFields,'',',')
endif

select *, count(*) as cntDups from (m.lcUniqueTableName) ;
   group by &lcGroupBy ;
   having cntDups>=2 ;
   into cursor curDups
 
select *, count(*) as cntUnique from (m.lcUniqueTableName) ;
   group by &lcGroupBy ;
   having cntUnique=1 ;
   into cursor curUnique

use in select(m.lcUniqueTableName)
delete file (m.lcUniqueTableName+"*")

>>Yeah, looks like it should work. I would probably do something like this:
>>
>>

>>FUNCTION IsDup
>>LOCAL llDupRec
>>
>>SELE LOCAL_HIV
>>SCATTER MEMO NAME oRecOne
>>
>>SELE CDCHIV
>>SCATTER MEMO NAME oRecTwo
>>
>>IF COMPOBJ( oRecOne, oRecTwo )
>>  *Duplicate
>>  llDupRec = .T.
>>ELSE
>>  *not a duplicate
>>  llDupRec = .F.
>>ENDIF
>>
>>RETURN llDupRec
>>

>>
>>Good luck,
>>John
>
>
>REMINDER, this only works on a record by record basis, it could take a while if you are calling it in a scan loop. If you just need to check 2 tables and want to do it quicker, use something like what Brian Givens suggested.
>
>John