I am on FB3.0.5

>> So, do the 211 rows returned only in

case 2 have null in any of the columns compared in the exists?

Both exists in case 1 and 2 are exactly the same without any modifications. And as i am looking for NOT exists than in query inside exists is empty resultset and then exists should return false. 

Thank you Set for the help. I must do one more test on monday. I must modify Case to comparision

CASE WHEN EXISTS() IS NULL THEN -1 ...

And we will see if exists can return something else then TRUE or FALSE8

Regards,