If I set a filter as in:

set filter to loc_id = 'A-21'
browse

the result will correctly show one record.
But if I issue:

set exact on
set filter to loc_id = 'A-21'
filterstr = filter()
select * where &filterstr

the result returns A-21, A-219, A-216, A-213 etc. Which is not what we want.

This can be overcome by setting the initial filter as:
set filter to loc_id == 'A-21'

but this construct is difficult in my situation. Is there another solution?

Thanks