多条件关联查询

  select
       <include refid="Detail_Refund"></include>
        from order_detail as a
        left join mj_refund as b
        on a.orderNo=b.orderNo
        where 1=1 and b.refundStatus=#{refundStatus}
        <if test="orderno!=null and orderno!=''">
            and a.orderNo=#{orderno}
        </if>