In the database is
ATable with fields FIELD_PK, FIELD2, .... and FIELD_PK is the primary
key field.

In a stored procedure I use
select FIRST 1 FIELD_PK from ATABLE
where FIELD2 > 0

Can I be certain that this selection is the same as
select FIRST 1 FIELD_PK from ATABLE
where FIELD2 > 0
order by FIELD_PK?