DECLARE @idoc INT
EXEC sp_xml_preparedocument @idoc OUTPUT,
     ?sDocs

UPDATE cash_flows
SET    date_revision = GETDATE(),
       payment_order = a.payment_order,
       amount = a.amount
FROM   cash_flows cf
       INNER JOIN OPENXML(@idoc, 'VFPData/doc_val_acc',  2 )
            WITH
            (
                payment_order VARCHAR( 64 ),
                date_info DATETIME,
                amount FLOAT,
                code_acc INT
            ) a
            ON  cf.code_acc = a.code_acc
            AND cf.date_info = a.date_info

/* все что не обновилось, вставится следующим запросом */

INSERT INTO cash_flows
  (
    date_revision,
    payment_order,
    code_acc,
    date_info,
    amount
  )
SELECT GETDATE() AS date_revision,
       a.payment_order,
       a.code_acc,
       a.date_info,
       a.amount
FROM   OPENXML(@idoc, 'VFPData/doc_val_acc',  2 )
       WITH
       (
           payment_order VARCHAR( 64 ),
           date_info DATETIME,
           amount FLOAT,
           code_acc INT
       ) a
WHERE  NOT EXISTS (
           SELECT  1 
           FROM   cash_flows cf
           WHERE  cf.code_acc = a.code_acc
                  AND cf.date_info = a.date_info
       )

EXEC sp_xml_removedocument @idoc