在货币列中求和负值

这可能就是你想要的:

SELECT 
  SUM(case when ReceiptAmt<0 then 0 else ReceiptAmt end) - 
  SUM(case when BalanceAmt<0 then 0 else BalanceAmt end) 
FROM Receipt            

余额是否也应该在where条款中?

WHERE ReceiptAmt > 0.00 
      AND BalanceAmt > 0.00