With settings ENGINEBEHAVIOR =70, vfp6 version sp5, vfp9 version sp2
joining 2 files
BACKOUTS
NOREPORT, where this file contains null values in field encounter_transaction_number_tx in certain rows

This code returns 10 records when run in vfp6 and 0 records when run in vfp9
select backouts.encounter_tracking_number_tx from backouts where backouts.encounter_tracking_number_tx;
not in (select noreport.encounter_tracking_number_tx from noreport) into cursor report;
group by backouts.encounter_tracking_number_tx

This code returns 10 records in BOTH vfp6 and vfp9
select backouts.encounter_tracking_number_tx from backouts where (backouts.encounter_tracking_number_tx;
not in (select noreport.encounter_tracking_number_tx from noreport WHERE NOT ISNULL(noreport.encounter_tracking_number_tx))) into cursor report;
group by backouts.encounter_tracking_number_tx

Is there a configuration option for vfp9 that will make it unnecessary to find and modify my old SQL statements for this condition?

TIA
Howie