Ranking SQL query - php

Question

I'm making kind of top-ten ranking in my app, and I'm stuck in the SQL query that I'll use for that.
I have 2 tables.
The 'posts' table stores the ID of the post autor(user_id), and the post content(and, of course, the entry ID).
+----+---------+--------------+
| ID | user_id | content |
+----+---------+--------------+
| 1 | 3 | Lorem Ipsum1 |
| 2 | 6 | Lorem Ipsum2 |
| 3 | 3 | Lorem Ipsum3 |
+----+---------+--------------+
The 'likes' table, stores ID of the person who liked the post(user_id), the post ID(post_id) and the like date witch is a timestamp(like_date).
+----+---------+---------+------------+
| ID | user_id | post_id | like_date |
+----+---------+---------+------------+
| 1 | 2 | 1 | 1491484851 |
| 2 | 5 | 1 | 1491484871 |
| 3 | 11 | 2 | 1491484891 |
+----+---------+---------+------------+
Every time a user like a post, an entry is created at the 'likes' table, and if the user unlike it, I just remove the entry.
And here's the deal. I want to grab the top 10 most liked users of the last 30 days. I want the query result to be something like this
+---------+-------+
| user_id | likes |
+---------+-------+
| 3 | 2 |
| 6 | 1 |
+---------+-------+
I've already tried a tons of queries and spent a couple of hours trying to solve that, but I just cant figure out how to.

Answer 1

This one should do the trick
select user_id, count(*)
from posts t1
join likes t2
on t1.ID = t2.post_id
where from_unixtime(t2.like_date) >= now() - interval 30 day
group by user_id
order by count(*) desc
limit 10

Answer 2

Assuming you mean "post_id" not "user_id" in your expected results:
SELECT post_id, count(*) as 'likes'
FROM likes
GROUP BY post_id
WHERE like_date >= DATE(NOW() - INTERVAL 30 DAY)
ORDER By 2 desc
LIMIT 10
Everything's in the likes table, so filter recent posts (WHERE), return/order by the count and onl retrieve the first 10 rows. There are other ways to achieve this...

Answer 3

You don't even need a join for this:
SELECT user_id, count(*) as numlikes
FROM likes l
WHERE like_date >= unix_timestamp() - 30*24*60*60
GROUP BY user_id
ORDER BY numlikes desc
LIMIT 10;
The like_date looks like a Unix timestamp, so we should treat it as one. This gets exactly 30 days from the current time to the second. If you want to count days from midnight:
WHERE like_date >= unix_timestamp(CURDATE() - interval 30 day)
EDIT:
If it is the user_id from the post, then you would use join to get that:
SELECT p.user_id, count(*) as numlikes
FROM likes l join
posts p
on l.post_id = p.id
WHERE l.like_date >= unix_timestamp() - 30*24*60*60
GROUP BY p.user_id
ORDER BY numlikes desc
LIMIT 10;