Get two different limits from mysql left join [closed] - php

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I want to display up to 3 posts form each category. Also I want to check each category have at least 3 posts (get the post count). Please see the table stretcher below
Category table
+---------+---------------+
| cat_id | cat_name |
+---------+---------------+
| 1 | cat name 1 |
| 2 | cat name 2 |
| 3 | cat name 3 |
+---------+---------------+
Posts table
+------+--------+-------+
| p_id | post | c_id |
+------+--------+-------+
| 1 | post 1 | 1 |
| 2 | post 2 | 1 |
| 3 | post 3 | 2 |
| 4 | post 1 | 2 |
| 5 | post 2 | 1 |
| 6 | post 3 | 3 |
| 6 | post 3 | 1 |
+------+--------+-------+
Query
if($results=$mysqli->query( SELECT * FROM categories LEFT JOIN posts ON posts.p_id= categories.cat_id WHERE posts.p_id= categories.cat_id ORDER BY cat_id LIMIT 0, 10")){
while($row = mysqli_fecth_array($results)){
//Do stuff
}
$results ->close();
}
Any example or comments are appreciated.

Answer 1

It is not possible to get up to 3 posts from each category in MySQL and sane query. You need support for window functions for that. I would preform a separate query for each category. You can read short info in this tag: https://stackoverflow.com/tags/window-functions/info
For the second part:
SELECT c_id, COUNT(*) FROM posts GROUP BY c_id;

Answer 2

select distinct (c.postid) , c.postname, s.category_name from posts c inner join category s on s.cat_id = c.cat_id group by c.cat_id having COUNT(c.cat_id) > 3 limit 3