SELECT 
  cscart_products_categories.product_id, 
  GROUP_CONCAT(
    IF(
      cscart_products_categories.link_type = "M", 
      CONCAT(
        cscart_products_categories.category_id, 
        "M"
      ), 
      cscart_products_categories.category_id
    )
  ) AS category_ids, 
  product_position_source.position AS position 
FROM 
  cscart_products_categories 
  INNER JOIN cscart_categories ON cscart_categories.category_id = cscart_products_categories.category_id 
  AND cscart_categories.storefront_id IN (0, 1) 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
  LEFT JOIN cscart_products_categories AS product_position_source ON cscart_products_categories.product_id = product_position_source.product_id 
  AND product_position_source.category_id = 6 
WHERE 
  cscart_products_categories.product_id IN (
    67841, 68817, 67790, 67789, 67788, 67787, 
    67786, 67785, 67784, 67783, 67782, 
    67781, 67780, 67779, 67778, 67777, 
    67776, 67775, 67774, 67773, 67772, 
    67771, 68694, 68693, 68661, 68532, 
    68124, 68123, 68692, 68662, 68573, 
    68531, 68374, 68361, 68199, 67871, 
    67844, 67843, 67840, 68201
  ) 
GROUP BY 
  cscart_products_categories.product_id