mysql_change_user() changes the logged in user
of the current active connection, or the connection given by the
link_identifier parameter. If a
database is specified, this will be the current database after
the user has been changed. If the new user and password
authorization fails, the current connected user stays active.
This function is deprecated and no longer exists in PHP.
The new MySQL username.
The new MySQL password.
The MySQL database. If not specified, the current selected database is used.
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() was called with no arguments. If by chance no connection is found or established, an E_WARNING level warning is generated.