Question

I’m trying to build a query that retrieves me, for each post, its respective count of images, comments, likes and favorites. All this data is in separate relational tables that allways store the id of the post.

However when I run the query 3 other pages come with exactly the same data as the first page.

So far I’ve coded this

SELECT * FROM
        (SELECT pst.* FROM posts as pst
        LEFT JOIN postcategories as pstcat
        ON pst.id = pstcat.id_post
        WHERE pst.date IS NOT NULL AND pst.date >= '2013-01-01 00:00:00' AND pst.date <= '2013-01-11 00:00:00' ) as res1  
        INNER JOIN
        (SELECT pst.*, count(pstcmt.id) as cmtCount
                        FROM posts as pst
                        LEFT JOIN userpostcomments as pstcmt
                        ON pst.id = pstcmt.id_post 
                        GROUP BY pst.id) as res2 ON res1.id = res2.id
        INNER JOIN
        (SELECT pst.id, count(pstlk.id) as lkCount
                        FROM posts as pst
                        LEFT JOIN userpostlikes as pstlk
                        ON pst.id = pstlk.id_post 
                        GROUP BY pst.id) as res3 ON res1.id = res3.id
        INNER JOIN
        (SELECT pst.id, count(pstfav.id) as favCount
                        FROM posts as pst
                        LEFT JOIN userpostfavorites as pstfav
                        ON pst.id = pstfav.id_post 
                        GROUP BY pst.id) as res4 ON res1.id = res4.id
        INNER JOIN
        (SELECT pst.id, count(pstimg.id) as imgCount
                        FROM posts as pst
                        LEFT JOIN postimages as pstimg
                        ON pst.id = pstimg.id_post 
                        GROUP BY pst.id) as res5 ON res1.id = res5.id

                        WHERE res1.deleted = 0 
                        AND res1.date IS NOT NULL 
                        GROUP BY res1.id
                        ORDER BY res1.date DESC 

Thank you

UPDATE : Updated query with ORDER BY as sugested. However the problem of data mirroring still exists

Answer 1

Maybe, this is what you want:

SELECT pst.id,
      COALESCE(cmtCount, 0) cmtCount,
      COALESCE(lkCount, 0) lkCount,
      COALESCE(pstfavCount, 0) pstfavCount,
      COALESCE(imgCount , 0) imgCount,
FROM posts as pst
        LEFT JOIN 
           (SELECT id_post, count(id) as cmtCount
                FROM userpostcomments GROUP BY id_post) as cmt
            ON pst.id = cmt.id_post
        LEFT JOIN 
           (SELECT id_post, count(id) as lkCount
                FROM userpostlikes GROUP BY id_post) as lk
            ON pst.id = lk.id_post
        LEFT JOIN 
           (SELECT id_post, count(id) as pstfavCount
                FROM userpostfavorites GROUP BY id_post) as pstfav
            ON pst.id = pstfav.id_post
        LEFT JOIN 
           (SELECT id_post, count(id) as imgCount
                FROM postimages GROUP BY id_post) as img
            ON pst.id = img.id_post
 WHERE pst.deleted = 0 
    AND pst.date >= '2013-01-01 00:00:00'
    AND pst.date <= '2013-01-11 00:00:00'
 ORDER BY pst.date DESC 

I think, this query more faster.

SELECT pst.id,
      COUNT(DISTINCT cmt.id) cmtCount,
      COUNT(DISTINCT lk.id) lkCount,
      COUNT(DISTINCT pstfav.id) pstfavCount,
      COUNT(DISTINCT img.id) imgCount,
FROM posts as pst
        LEFT JOIN userpostcomments cmt
            ON pst.id = cmt.id_post
        LEFT JOIN  userpostlikes lk
            ON pst.id = lk.id_post
        LEFT JOIN userpostfavorites  pstfav
            ON pst.id = pstfav.id_post
        LEFT JOIN postimages  img
            ON pst.id = img.id_post
 WHERE pst.deleted = 0 
    AND pst.date >= '2013-01-01 00:00:00'
    AND pst.date <= '2013-01-11 00:00:00'
 GROUP BY pst.id
 ORDER BY pst.date DESC