SELECT icms, cfop, cst, base_calc_icms, ((base_calc_icms * icms) / 100) AS valor_icms
FROM
(
    SELECT VEN.icms, CASE
                        WHEN tributa = 'T' THEN '5102'
                        WHEN tributa = 'F' THEN '5405'
                        ELSE '5102'
                     END AS cfop,

                     CASE
                        WHEN tributa = 'T' THEN '000'
                        WHEN tributa = 'F' THEN '060'
                        WHEN tributa = 'I' THEN '040'   -- e REDUÇÃO? COMO DETECTAR?
                        ELSE '000'
                     END AS cst,
           SUM(VEN.total) AS base_calc_icms
    FROM vendas VEN
    WHERE VEN.loja = :iloja
      AND VEN.DATA = :idata
      AND VEN.ecf  = :iecf
      AND VEN.STATUS = 'VE'
      AND VEN.cancelado = ' '
    GROUP BY VEN.icms, cfop, cst
)