Syntax:
OLD_PASSWORD(str)

OLD_PASSWORD() was added when the implementation of PASSWORD() was
changed in MySQL 4.1 to improve security. OLD_PASSWORD() returns the
value of the pre-4.1 implementation of PASSWORD() as a string, and is
intended to permit you to reset passwords for any pre-4.1 clients that
need to connect to your MySQL server without locking them out. See
http://dev.mysql.com/doc/refman/5.5/en/password-hashing.html.

The return value is a string in the connection character set.

*Note*:

Passwords that use the pre-4.1 hashing method are less secure than
passwords that use the native password hashing method and should be
avoided.

URL: http://dev.mysql.com/doc/refman/5.5/en/encryption-functions.html

