most secure password scheme

Hello,

I have a few questions on password schemes. Is SHA512 the most secure? Is there a difference between SHA512 and SHA512-CRYPT? What about SSHA512 and SSH512-CRYPT?

Is there a problem with this sql statement:

UPDATE virtual_users SET password=CONCAT(‘{SHA256-CRYPT}’, ENCRYPT (‘Password Goes Here’, CONCAT(‘$5$’, SUBSTRING(SHA(RAND()), -16)))) WHERE user=’user@example.com’;

I'm getting an error 1064 at the ending email address.

Thanks. Dave.