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 (
    66018, 66017, 66016, 66015, 66014, 66013, 
    66012, 66011, 66010, 66009, 66008, 
    66007, 66006, 66005, 66004, 66003, 
    66002, 66001, 66000, 65999, 65998, 
    65997, 65996, 65995, 65994
  ) 
  AND cscart_product_prices.lower_limit = 1 
  AND cscart_product_prices.usergroup_id IN (0, 1) 
GROUP BY 
  cscart_product_prices.product_id