Yes, you are right. My file consists the timestamp data as Mar 23, 2015 12:00:00 PM.000. I confused this fact with the fact that HANA Studio shows month name instead of month number even if in the table month number is stored.
I will check the whole table to find records with different date format and fix them and then run again you code. As you mentioned, it works in your experiments. Thank you for your help.
Best,
Rasoul