Hi Nakul,
Why don't you want to handle the special characters before loading the data to HANA.?
What is the ETL tool you are using for loading into HANA?
Based on your input we can validate the data and load the clean data into HANA. It can be done easily using SAP BODS using Validation Transform.
If you still want to handle it in HANA, you may need to write a generic procedure in HANA and reload the data into the table or you may need to keep your "if" conditions as calculated columns in the models and remove them ( This makes more if's depending on possible special characters).
Regards,
Krishna Tangudu