mybatis的映射xml中动态设置orderby方式

List<DzRainDetail> queryDetail(@Param("masterId") int masterId, 
@Param("country") String country, 
@Param("sort") String sort);

<select id="queryDetail" resultMap="DetailResultMap">
    SELECT rd.id, st.address, rd.water, st.d_name
    FROM dzzhyj.dz_rain_detail rd
    INNER JOIN dzzhyj.DZ_RAIN_STATioN st ON rd.station_code = st.code
    WHERE rd.master_id = #{masterId}
    AND st.country = #{country}
    <if test="sort.compareTo('d') == 0">
        ORDER BY st.d_name ASC
    </if>
    <if test="sort.compareTo('water') == 0">
        ORDER BY rd.water DESC
    </if>
</select>

<if test="sort == 'd'">
    ORDER BY st.d_name ASC
</if>
<if test="sort == 'water'">
    ORDER BY rd.water DESC
</if>