SELECT 
  cscart_product_prices.product_id, 
  MIN(
    IF(
      cscart_product_prices.percentage_discount = 0, 
      cscart_product_prices.price, 
      cscart_product_prices.price - (
        cscart_product_prices.price * cscart_product_prices.percentage_discount
      )/ 100
    )
  ) AS price 
FROM 
  cscart_product_prices 
WHERE 
  cscart_product_prices.product_id IN (
    68974, 68973, 68972, 68971, 68970, 68969, 
    68968, 68967, 68966, 68965, 68964, 
    68963, 68962, 68961, 68960, 68959, 
    68958, 68957, 68956, 68955, 68954, 
    68953, 68952, 68951, 68950, 68949, 
    68948, 68947, 68946, 68945, 68321, 
    68290, 68289, 68288, 68286, 68285, 
    68284, 68283, 68282, 68281
  ) 
  AND cscart_product_prices.lower_limit = 1 
  AND cscart_product_prices.usergroup_id IN (0, 1) 
GROUP BY 
  cscart_product_prices.product_id