MySQL循环()
<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 >= #{item.startTime} AND TM < #{item.endTime} ) ,0)AS #{item.asName}
</foreach>
FROM
WR_MP_HOURW_R
WHERE
TM >= #{startTime}
AND TM < #{endTime}
GROUP BY
<foreach collection="mpHourwRList" item="item" index="index" separator=",">
#{item.asName}
</foreach>
</select>