feature(结算): 已出账单生成时，退出逻辑变化

service/settle_account_bill/settle_account_bill.go

@@ -204,7 +204,7 @@ func (s Service) GenerateBill() error {
 		return err
 	}
 	err = all.Structs(&mains)
-	if err != nil {
+	if err != nil || len(mains) == 0 {
 		if err == sql.ErrNoRows {
 			return nil
 		}