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 (
    18516, 51007, 51004, 51005, 51010, 51008, 
    51012, 51013, 51011, 51015, 51006, 
    51021, 51016, 51024, 51017, 51019, 
    51018, 51022, 51014, 51045, 51422, 
    51025, 51440, 51029, 51424, 51429, 
    51442, 51060, 51436, 51430, 51433, 
    51027, 51063, 51020, 51067, 51423, 
    51431, 51435, 51028, 51031, 51062, 
    51042, 51441, 51432, 51434, 51030, 
    51032, 51033, 51425, 51026, 51035, 
    51059, 51069, 51070, 51038, 51066, 
    51023, 51041, 51056, 51040, 51050, 
    51065, 51039, 51052
  ) 
GROUP BY 
  p.product_id