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 (
    51007, 51004, 51005, 51010, 51012, 51013, 
    51011, 51015, 51006, 51021, 51016, 
    51017, 51018, 51024, 51019, 51022, 
    51014, 51045, 51025, 51029, 51020, 
    51027, 51028, 51031, 51033, 51030, 
    51032, 51026, 51042, 51035, 51039, 
    51041
  ) 
GROUP BY 
  p.product_id