>select distinct rep, .t. as SA_flag from myTable ; where pub = "SA" ;union ;
select distinct rep, .f. as SA_flag from myTable ;
where rep not in (select distinct rep from myTable where pub="SA") ;order by 1

Assuming a significant size "myTable", how would that statement compare with:
Select distinct rep, .t. as SA_Flag from myTable where pub="SA";
union;
Select distinct rep, .f. as SA_Flag from myTable where NOT (pub="SA")

It seems the first statement would be querying the same set twice.

I thought there was an "in-line" way to get a unique value from a group, but i guess the two-step union will work (almost) as effectively.