SQL Left Join with verification on each table - sql

Question

First, my SQL skils are really bad.
Here is my tables :
Message :
id | title | arrayusers
1 |Title1 | a:2:{i:1;i:1;i:5;i:5;}
2 |Title2 | a:2:{i:1;i:1;i:5;i:5;}
3 |Title3 | a:2:{i:1;i:1;i:5;i:5;}
4 |Title4 | a:2:{i:1;i:1;i:5;i:5;}
5 |Title5 | a:2:{i:1;i:1;i:5;i:5;}
6 |Title6 | a:2:{i:1;i:1;i:5;i:5;}
Read :
id | status | userid | message_id
1 | 0 | 5 | 1
2 | 0 | 1 | 2
3 | 0 | 5 | 2
4 | 0 | 1 | 3
5 | 0 | 5 | 4
6 | 1 | 1 | 5
7 | 1 | 5 | 5
7 | 1 | 5 | 6
I use the userid 1 for my test :
My goal, is to get all lines from Message, where my user 1 is in arrayusers with a LIKE(i:1;i:1;)
And user 1 not in table Read (userid), with the status equal to 0. If another user (5) but not me (user 1) is in Read table, I want to see my Message line
With the data above, I want to return the id 1 / 4 from Message table
I started a request with Left join, but my request hide line id 1 and 4 because there is another user in this table with this id.
SELECT * FROM message as m
LEFT JOIN read as r ON m.id = r.message_id
WHERE m.arrayusers LIKE '%i:1;i:1;%'
AND r.id IS NULL
Hope you understand my request.
Someone can help me to debug my request ?
Thanks

Answer 1

I'd use NOT EXISTSor NOT IN to look up the status in the read table:
select *
from message
where arrayusers like '%i:1;i:1;%'
and id not in
(
select message_id
from read
where userid = 1
and status = 0
);
As to your own query: You are merely missing the criteria on the read table:
SELECT m.*
FROM message as m
LEFT JOIN read as r ON m.id = r.message_id and r.userid = 1 and r.status = 0
WHERE m.arrayusers LIKE '%i:1;i:1;%'
AND r.id IS NULL;

Answer 2

What is the use of AND r.id IS NULL? Please remove this condition and check:
SELECT * FROM message as m
LEFT JOIN read as r ON m.id = r.message_id
WHERE m.arrayusers LIKE '%i:1;i:1;%'
AND r.id IS NULL