Re: Error : (1045) Access denied for user 'root'@'localhost' (using password: NO)

[Peter Brawley]

Basic PHP debugging: stub out the problem values, have your script echo the values of $localhost, $username, $password, $database, and compare with the results of this query in the mysql client ...

select user, host, authentication_string from mysql.user;

... or if the MySQL version < 5.7 ...

select user, host, password from mysql.user;