Select all from table where user_id exists in both tables - mysql

Question

I am creating a small chat/ message system. I have four tables: thread, thread_participant, message and message_read_state. I know it might not be the best solution, but I just wanted to give this a go for a project of mine. How can i select all new messages coming in for a specific user without selecting the his/her own message?
thread table
id
----------
1
2
thread_participant table
thread_id user_id
---------- --------
1 6
1 7
message table
id thread_id send_date message sending_user_id
---------- -------- -------- -------- --------
1 1 2016-05-12 HELLO 7
2 1 2016-05-12 HELLO BACK 6
message_read_state
message_id user_id s read_date
----- -------- --------
1 6 2016-05-12
2 7 2016-05-12
EDIT
What I have so far. This select all the threads I have participated, but I would like to display only the incoming message, without my response.
SELECT message.id, message.send_date, message.message, tbl_users.user_id, message.thread_id
, (SELECT message_read_state.read_date
FROM message_read_state
WHERE message_read_state.message_id = message.id
and message_read_state.user_id = 6) AS ReadState
FROM message INNER JOIN tbl_users ON message.sending_user_id = tbl_users.user_id
WHERE ( message.id in
( SELECT (message.id)
FROM thread_participant INNER JOIN message
ON thread_participant.thread_id = message.thread_id
WHERE thread_participant.user_id = 6
GROUP BY thread_participant.user_id
)
)
ORDER BY message.send_date ASC;

Answer 1

What about this;)
SELECT message.id, message.send_date, message.message, tbl_users.user_id, message.thread_id
, (SELECT message_read_state.read_date
FROM message_read_state
WHERE message_read_state.message_id = message.id
and message_read_state.user_id = 6) AS ReadState
FROM message INNER JOIN tbl_users ON message.sending_user_id = tbl_users.user_id
WHERE ( message.id in
( SELECT (message.id)
FROM thread_participant INNER JOIN message
ON thread_participant.thread_id = message.thread_id
WHERE thread_participant.user_id = 6
GROUP BY thread_participant.user_id
)
)
AND message.sending_user_id <> 6
ORDER BY message.send_date ASC;
I've just add AND message.sending_user_id <> 6 in your original sql. If you don't want response, just let sending_user_id is not you, then you get what you want. :D