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 (
    21567, 51083, 22715, 51082, 51085, 51081, 
    51096, 51097, 51098, 51100, 51099, 
    22716, 51123, 51122, 51121, 92, 49, 
    51129, 51128, 51127, 51126, 51125, 
    48, 51176, 51174, 51173, 51172, 91, 
    51221, 137, 51224, 51223, 126, 51343, 
    51342, 51341, 51340, 47, 105, 50989, 
    31, 51366, 51367, 51368, 51369, 46, 
    51370, 51371, 51372, 51373, 51452, 
    51453, 88, 51395, 51396, 51397, 51555, 
    51556, 51496
  ) 
GROUP BY 
  p.product_id