MySQL循環（）

<select id="getByList" resultMap="HourwRResultMap">
        SELECT
        <foreach collection="mpHourwRList" item="item" index="index" separator=",">
            IFNULL(( SELECT HOUR_W FROM WR_MP_HOURW_R WHERE MP_CD = #{item.mpCd} AND TM &gt;= #{item.startTime} AND TM &lt; #{item.endTime} ) ,0)AS #{item.asName}
        </foreach>
        FROM
        WR_MP_HOURW_R
        WHERE
        TM &gt;= #{startTime}
        AND TM &lt; #{endTime}
        GROUP BY
        <foreach collection="mpHourwRList" item="item" index="index" separator=",">
            #{item.asName}
        </foreach>
    </select>