QuickSort in ascending order using Haskell

-- QuickSort in Ascending order.
qsort :: Ord a => [a] -> [a]
qsort [] = []
qsort (x : xs) = qsort small_list ++ [x] ++ qsort large_list
                 where
                    small_list = [a | a <- xs, a <= x]
                    large_list = [b | b <- xs, b > x]