If you enter username 'jdoe' and the password 'password', this code produces this SQL command:

SELECT FROM tblUsers WHERE USERNAME = 'jdoe' AND PASSWORD = 'password'

SELECT FROM tblUsers WHEN USERNAME = 'jdoe' AND PASSWORD = 'password'

SELECT FROM tblUsers WHICH USERNAME = 'jdoe' AND PASSWORD = 'password'

SELECT FROM tblUsers WHEN USERNAME = 'jdoe' OR PASSWORD = 'password'