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 (
    64531, 63919, 63727, 64535, 64525, 64524, 
    64509, 64424, 64100, 64099, 63197, 
    64508, 64507, 64506, 64505, 64429, 
    64428, 64427, 64426, 64425, 64393, 
    64208, 63573, 63572, 61775, 61755, 
    64145, 64122, 64121, 64120, 61891, 
    64080, 64079, 63775, 63898, 63897, 
    63871, 63718, 63301, 63300
  ) 
GROUP BY 
  cscart_products_categories.product_id