MYSQL query check if user like - php

Question

I'm asking for query statement I have two tables
first table 'posts' :
post_id title Userid
1 test 1
The other table is 'likes'
userid post_id
1 1
I need single query to check if user like this photo or not in bulk select my solution is very poor :
SELECT * FROM `table` WHERE x = x LIMIT 100;
and give it foreach and make query for every row :
foreach($results as $v)
{
$data[1] = $v;
$data[1]['is_like'] = SELECT COUNT(*) FROM likes WHERE userid = 1;
}
1 is the already login user id
I need to single query to return post_id,.. etc and filed like is_like

Answer 1

Assuming likes can have only 1 row with the same (user_id,post_id) :
SELECT p.* ,
CASE WHEN
l.id IS NULL THEN 0
ELSE 1
END as is_liked
FROM posts p
LEFT JOIN likes l ON l.user_id = p.user_id and l.post_id =p.post_id
If not (multiple rows in likes for a given (user_id,post_id) ) :
SELECT p.* ,
CASE WHEN
l.user_id IS NULL THEN 0
ELSE 1
END as is_liked
FROM posts p
LEFT JOIN
(
SELECT DISTINCT user_id,post_id FROM likes
) l ON l.user_id = p.user_id and l.post_id =p.post_id;
Or
SELECT p.* ,
CASE
WHEN EXISTS (SELECT NULL FROM likes l
WHERE l.user_id = p.user_id and l.post_id =p.post_id) THEN 1
ELSE 0
END as is_liked
FROM posts p
Update
I hope I got a better understanding of the question now. My assumption : posts.user_id is id of user who created post; like table stores information about who likes the post. Thus, to check all posts and whether a particular like them you need ($login_user_id should be escaped properly)
SELECT p.* ,
CASE
WHEN EXISTS (SELECT NULL FROM likes l
WHERE l.user_id = $login_user_id and l.post_id =p.post_id) THEN 1
ELSE 0
END as is_liked
FROM posts p

Answer 2

SELECT
p.post_id,
p.title,
IF(l.post_id IS NOT NULL,1,0) as like
FROM posts as p
LEFT JOIN likes as l ON l.post_id = p.post_id AND l.userid = p.userid
WHERE p.Userid = 1
If post_id in likes table is available it will return 1 else 0.

Answer 3

Something like this should work as a single query (untested, of course - you didn't provide much data to use for testing):
select
p.title, count(l.post_id)
from
`posts` p
inner join
`likes` l
on
l.userid = p.userid and l.post_id = p.post_id
where
p.userid = loggedinuserID
group by
p.userid
This will give you a count of the total posts the specified user has liked.