MySQL 5.6

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CREATE TABLE `users` (
 `id` int(11) NOT NULL AUTO_INCREMENT,
 `username` varchar(16) DEFAULT NULL,
 PRIMARY KEY (`id`),
 UNIQUE KEY `username` (`username`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4;

CREATE TABLE `posts` (
 `id` int(11) NOT NULL AUTO_INCREMENT,
 `user` int(11) NOT NULL,
 `content` text NOT NULL,
 PRIMARY KEY (`id`),
 KEY `posts_ibfk_1` (`user`),
 CONSTRAINT `posts_ibfk_1` FOREIGN KEY (`user`) REFERENCES `users` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4;

CREATE TABLE `following` (
 `user_id` int(11) NOT NULL,
 `followed` int(11) NOT NULL,
 `notifications` tinyint(1) NOT NULL DEFAULT '1',
 UNIQUE KEY `user_id` (`user_id`,`followed`),
 KEY `following_ibfk_2` (`followed`),
 CONSTRAINT `following_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
 CONSTRAINT `following_ibfk_2` FOREIGN KEY (`followed`) REFERENCES `users` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO users(username) VALUES('testUsername');
INSERT INTO users(username) VALUES('secondUser');

INSERT INTO following(user_id, followed) VALUES(1, 2);

INSERT INTO posts(user, content) VALUES(1, 'This is my first post');
INSERT INTO posts(user, content) VALUES(1, 'Second post!');
INSERT INTO posts(user, content) VALUES(2, 'Hello this is another user speaking');
select p.id, p.content, u.id AS user_id, u.username
from (
  select *
  from posts
  where user = 1
     or user in (select user_id from following where followed = 1)
) p inner join users u on u.id = p.user  
order by p.id desc limit 10


id
content
user_id
username


2
Second post!
1
testUsername

1
This is my first post
1
testUsername


select p.id, p.content, u.id AS user_id, u.username
from (
  select *
  from posts
  where user = 2
     or user in (select user_id from following where followed = 2)
) p inner join users u on u.id = p.user  
order by p.id desc limit 10


id
content
user_id
username


3
Hello this is another user speaking
2
secondUser

2
Second post!
1
testUsername

1
This is my first post
1
testUsername

id	content	user_id	username
2	Second post!	1	testUsername
1	This is my first post	1	testUsername

id	content	user_id	username
3	Hello this is another user speaking	2	secondUser
2	Second post!	1	testUsername
1	This is my first post	1	testUsername