-- | Report the top /k/ customers by account balance from some country.
topCustAcct :: Text -> Integer -> Q [(Text, Decimal)]
topCustAcct n k =
    topK k snd [ tup2 (c_nameQ c) (c_acctbalQ c)
               | c <- customers
               , c `custFromNation` n
               ]
topCustAcct :: Text -> Integer -> Q [(Text, Decimal)]
topCustAcct n k =
    topK k snd [ tup2 (c_nameQ c) (c_acctbalQ c)
               | c <- customers
               , c `custFromNation` n
               ]
topCustAcct n k =
    topK k snd [ tup2 (c_nameQ c) (c_acctbalQ c)
               | c <- customers
               , c `custFromNation` n
               ]