What is the difference between SHA256 and Scrypt?

[Versatile]

what is the difference between SHA256 and Scrypt and which one must be used for mining for better results?

[dspair]

Not exactly sure what you mean. Different coins have different mining algorithms, you can't mine Scrypt coin by solving SHA256 and vice versa.

[Bharat]

some googling gives these 

coinpursuit.com/pages/bitcoin-altcoin-SHA-256-scrypt-mining-algorithms/

reddit.com/r/BitcoinMining/comments/1ztaau/what_is_the_difference_between_sha256_and_scrypt/