优化sql

mec-biz/src/main/resources/config/mybatis/StudentPaymentOrderMapper.xml

@@ -1045,7 +1045,7 @@
                ifnull(a.coupon_remit_fee_, 0)     as totalAmount,
                a.actual_amount_                   as actualAmount,
                a.balance_payment_amount_          as balanceAmount,
-               a.remit_fee_ + a.coupon_remit_fee_ as totalRemitFee,
+               ifnull(a.remit_fee_,0) + ifnull(a.coupon_remit_fee_,0) as totalRemitFee,
                a.create_time_ as createTime,
                a.pay_time_ as payTime,
                a.trans_no_ as transNo,