How to select the sender(data) and the recipient(data) using one SQL-query?

Question

So, I'm using PHP and MySQL. I have a table 'notifications' and a table 'users'. The notification gives a sender and a recipient. I've done some research and tried some things out, but I couldn't come to a solution. The following SQL query gives me the data set in the notification and also the recipient data, but how can I also select the sender data from the users table in one query?

SELECT notifications.id,notifications.recipient_id,notifications.sender_id,notifications.unread,notifications.type,notifications.parameters,notifications.created_at,users.id AS user_id,users.username 
FROM notifications, users 
WHERE users.id = notifications.recipient_id;

Answer 1

SELECT 
    notifications.id,
    notifications.recipient_id,
    notifications.sender_id,
    notifications.unread,
    notifications.type,
    notifications.parameters,
    notifications.created_at,
    users1.id AS user_id_recipient,
    users1.username  AS username_recipient,
    users2.id AS user_id_sender,
    users2.username  AS username_sender
FROM notifications
INNER JOIN users AS users1 ON users1.id = notifications.recipient_id
INNER JOIN users AS users2 ON users2.id = notifications.sender_id