SQL cannot execute on live server - php

Question

I am trying to exectute the following on the live server but it does not execute. On the local host everything is fine. I am able to execute other sql on the live server tho
$mysqli = new mysqli("localhost", "username", "password", "database");
if(isset($_POST['username'])&& isset($_POST['password']) ){
$username =$_POST['username'];
$password = md5($_POST['password']);
if ($mysqli) {
/* Prepared statement, stage 1: prepare */
if (!($stmt = $mysqli->prepare("select acc.accountId, acc.firstname, prof.imagename from accounts acc inner join profilepicture prof on prof.accountId=acc.accountId where acc.emailAddress=(?) and acc.password=(?)"))) {
echo "Prepare failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
/* Prepared statement, stage 2: bind and execute */
$stmt->bind_param("ss", $username,$password);
$stmt->execute();
$result = $stmt->get_result();
$row = $result->fetch_assoc();
if(!empty($row)){
`enter code here`
`enter code here`// STATEMENTS TO EXECUTE IF DETAILS EXISTS
}

Answer 1

This could be the reason: You are logging into mysql with no default database, no username and no password
$mysqli = new mysqli("localhost", "", "", "");
should be something like this:
$mysqli = new mysqli("localhost", "user", "password", "database");
Read this http://php.net/manual/en/mysqli.quickstart.connections.php

Answer 2

In the live server or cpanel.. go to mysql section create the database and user and password... and give that user the permission to edit update and delete.. then in the
$mysqli = new mysqli("localhost", "", "", "");
add all the three the username password and database name..then.. it will work fine..
Hope it works