fix:撤销折扣率为0

src/jfw/modules/bigmember/src/entity/portrailUtil.go

@@ -75,7 +75,7 @@ func CalculationRate(buyget, bidamount float64) interface{} {
 	if buyget > 0 {
 		return (buyget - bidamount) / buyget
 	}
-	return 0
+	return nil
 }
 
 //计算占比