SELECT 
  p.product_id, 
  ifnull(
    count(dp.post_id), 
    0
  ) as discussion_amount_posts 
FROM 
  cscart_discussion 
  INNER JOIN cscart_products as p ON (
    cscart_discussion.object_id = p.product_id
  ) 
  INNER JOIN cscart_discussion_posts as dp ON (
    cscart_discussion.thread_id = dp.thread_id 
    AND cscart_discussion.object_type = 'P' 
    AND cscart_discussion.company_id = 1
  ) 
WHERE 
  dp.status = 'A' 
  and p.product_id in (
    51529, 51459, 51457, 51460, 51501, 51530, 
    51464, 51051, 51053, 51551, 51478, 
    51469, 51510, 51486, 51531, 51467, 
    51047, 51461, 51044, 51475, 51477, 
    51473, 51437, 51540, 51048, 51525, 
    51458, 51463, 51516, 51532, 51545, 
    51492
  ) 
GROUP BY 
  p.product_id