I'm trying to ascertain if there's any tangible difference in using "where not isnull(Product)" vs "Where len(Product) > 0 "
1. load * where len(Concat_Flag_Unpivot) > 0 ;
2. load * where not isnull(Concat_Flag_Unpivot) ;
My understanding is that both 1 and 2 will yield same results but they're not.
Isnull() is only true by real NULL whereby an empty fieldvalue like '' or any kind of spaces like ' ' are not NULL in the sense of isnull(). This is very well explained here: NULL handling in QlikView.