PHP：为数组中的每个帖子添加评论计数

Question

I have 2 models "post_model" and "comment_model"

in Post_controller I get a result array from post_model which has all the posts.

I'm trying to add comments count for each post but I couldn't and need help.

• comment table has post_id.

Please let me know how to handle this. Thanks in advance.

Answer 1

Try this,

SELECT 
  p.post_id,
  (SELECT count(c.post_id) FROM comments c WHERE c.post_id = p.post_id) cnt 
FROM posts p 
GROUP BY p.post_id LIMIT 5

Hope this will solve your problem.

Answer 2

Something like this should give you the number of comments for each post:

SELECT 
COUNT(*) AS comment_cnt, post_id 
FROM comment_table 
GROUP BY post_id;

Then you can traverse the result set and enrich the corresponding post objects. If you want to count comments only for some specific posts and you know their post_id, you could do something like:

SELECT 
COUNT(*) AS comment_cnt, post_id 
FROM comment_table 
WHERE post_id IN (post_id1, post_id2, ...) 
GROUP BY post_id;

Answer 3

SELECT p.post_id, p.post_title, p.post_content, p.user_id,count(c.post_id)
FROM posts p 
LEFT JOIN comments c USING(post_id)
GROUP BY p.post_id, p.post_title, p.post_content, p.user_id;