I need to apply SHA-256 hashing on two columns while extracting the data. If any one has done it, please share how to do it.
To calculate the hash values within the DB you would need to write a UDF. A sha1 UDF is available in the download section but I am not aware of an SHA256 implementation.
Alternative is to extract the data and post process it.
Do you use a ETL tool? Some provide hashing functions.