Syntax:
SET PASSWORD syntax for MySQL 5.7.6 and up:

*Note*: SET PASSWORD is deprecated as of MySQL 5.7.6 and will be
removed in a future MySQL release. ALTER USER is now the preferred
statement for assigning passwords. For example: ALTER USER user
IDENTIFIED BY 'auth_string';

The SET PASSWORD statement assigns a password to a MySQL user account:

o With no FOR user clause, this statement sets the password for the
  current user:

SET PASSWORD = password_option;

  Any client who connects to the server using a nonanonymous account
  can change the password for that account. To see which account the
  server authenticated you as, invoke the CURRENT_USER() function:

SELECT CURRENT_USER();

o With a FOR user clause, this statement sets the password for the
  named account, which must exist:

SET PASSWORD FOR 'jeffrey'@'localhost' = password_option;

  In this case, you must have the UPDATE privilege for the mysql
  database.

When the read_only system variable is enabled, SET PASSWORD requires
the SUPER privilege in addition to any other required privileges.

If a FOR user clause is given, the account name uses the format
described in http://dev.mysql.com/doc/refman/5.7/en/account-names.html.
The user value should be given as 'user_name'@'host_name', where
'user_name' and 'host_name' are exactly as listed in the User and Host
columns of the account's mysql.user table row. If you specify only a
user name, a host name of '%' is used. For example, to set the password
for an account with User and Host column values of 'bob' and
'%.example.org', write the statement like this:

SET PASSWORD FOR 'bob'@'%.example.org' = PASSWORD('cleartext password');

The password can be specified in these ways:

o Using the PASSWORD() function

  The 'auth_string' function argument is the cleartext (unencrypted)
  password. PASSWORD() hashes the password and returns the encrypted
  password string for storage in the mysql.user account row.

  The old_passwords system variable value determines the hashing method
  used by PASSWORD(). If SET PASSWORD rejects the password as not being
  in the correct format, it may be necessary to change old_passwords to
  change the hashing method. For example, if the account uses the
  mysql_native_password plugin, the old_passwords value must be 0:

SET old_passwords = 0;
SET PASSWORD FOR 'jeffrey'@'localhost' = PASSWORD('mypass');

  If the old_passwords value differs from that required by the
  authentication plugin, the hashed password value returned by
  PASSWORD() is not acceptable for that plugin, and attempts to set the
  password produce an error. For example:

mysql> SET old_passwords = 1;
mysql> SET PASSWORD FOR 'jeffrey'@'localhost' = PASSWORD('mypass');
ERROR 1372 (HY000): Password hash should be a 41-digit hexadecimal number

  Permitted old_passwords values are described later in this section.

o Using the OLD_PASSWORD() function (permitted before MySQL 5.7.5
  only):

  The 'auth_string' function argument is the cleartext (unencrypted)
  password. OLD_PASSWORD() hashes the password using pre-4.1 hashing
  and returns the encrypted password string for storage in the
  mysql.user account row. This hashing method is appropriate only for
  accounts that use the mysql_old_password authentication plugin.

  *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. Pre-4.1 passwords are deprecated and support for them is
  removed in MySQL 5.7.5. Consequently, OLD_PASSWORD() is deprecated
  and is removed in MySQL 5.7.5.

o Using a string without PASSWORD() or OLD_PASSWORD()

  For this syntax, the meaning differs in MySQL 5.7.6 and up from
  earlier versions:

  o As of MySQL 5.7.6, SET PASSWORD interprets the string as a
    cleartext string and hashes it appropriately for the account
    authentication plugin before storing it in the mysql.user account
    row.

  o Before MySQL 5.7.6, SET PASSWORD interprets the string as a hashed
    password value to be stored directly. The string must be hashed in
    the format required by the account authentication plugin.

For more information about setting passwords, see
http://dev.mysql.com/doc/refman/5.7/en/assigning-passwords.html

URL: http://dev.mysql.com/doc/refman/5.7/en/set-password.html

