最近在项目中遇到一个，需要根据传入的存有id的list，计算值，再起别名
<if test="channelList != null and channelList.size()>0"> <foreach collection="channelList" index="index" item="item" open="" separator="," close=""> SUM(CASE WHEN ccs.sub_type =#{item} AND ccs.type = 1 THEN ccs.num ELSE 0 END) AS ‘dispatchNum${item}‘ </foreach> </if>
原文：http://www.cnblogs.com/chn58/p/5630881.html