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 (
    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
  ) 
  AND cscart_product_prices.lower_limit = 1 
  AND cscart_product_prices.usergroup_id IN (0, 1) 
GROUP BY 
  cscart_product_prices.product_id