Syntax:
PASSWORD(str)

Calculates and returns a hashed password string from the cleartext
password str and returns a nonbinary string in the connection character
set, or NULL if the argument is NULL. This function is the SQL
interface to the algorithm used by the server to encrypt MySQL
passwords for storage in the mysql.user grant table.

The password hashing method used by PASSWORD() depends on the value of
the old_passwords system variable:

URL: http://dev.mysql.com/doc/refman/5.6/en/encryption-functions.html

