ibatis 的 GroupBy属性的使用

ibatis的groupby的用处很多，比如把数据展示成树结构，目录结构等等。

ibatis的使用方法：

定义一个 resultMap，如下。

<resultMap id="SpreadGroupByPackageID" class="TChannelProduct"   
       groupBy="productId,channelId

"> 
       
        <result property="productId" column="productId"

 />
        <result property="channelId" column="channelId

" />
  
        <result property="channelProductlist" resultMap="cn.emag.product.domain.TChannelProduct.subchannelProduct

" />  
    </resultMap>

还有一个一个resultMap，内容如下：

<resultMap id="subchannelProduct

" class="TChannelProduct">  
        <result property="id" column="id" />
        <result property="spreadStartTime" column="spreadStartTime" />
        <result property="spreadEndTime" column="spreadEndTime" />
        <result property="productPageUrl" column="productPageUrl" />
        <result property="productTargetUrl" column="productTargetUrl" />
        <result property="isReferValid" column="isReferValid" />
        <result property="businessMdId" column="businessMdId" />
        <result property="bcidCode" column="bcidCode" />
        <result property="productType" column="productType" />
        <result property="balanceChannelId" column="balanceChannelId" />
        <result property="businessMdName" column="businessMdName" />
        <result property="businessMdCode" column="businessMdCode" />
        <result property="productId" column="productId" />
        <result property="channelId" column="channelId" />
        <result property="spreadState" column="spreadState" />
        <result property="channelName" column="channelName" />
        <result property="channelCorpType" column="channelCorpType" />
        <result property="companyCode" column="companyCode" />
        <result property="companyName" column="companyName" />
    </resultMap>

sql内容：

<select id="findSpreadGroupByPackageID" parameterClass="map" resultMap="SpreadGroupByPackageID">
select
cp.id  as id,
cp.spread_start_time as spreadStartTime,
cp.spread_end_time   as spreadEndTime,
cp.product_page_url as productPageUrl,
cp.Product_Target_Url  AS productTargetUrl,
cp.is_refer_valid as isReferValid,
cp.business_md_id as businessMdId,
CP.Bcid_Code AS bcidCode,
cp.product_type AS productType,
cp.balance_channel_id AS balanceChannelId,
bu.business_model_name as businessMdName,
bu.business_model_code as businessMdCode,
CP.PACKAGE_ID AS PRODUCTID

,
cp.channel_id as channelId

,
cp.SPREAD_STATE as spreadState,
ci.channel_name  as channelName,
ci.CHANNEL_CORP_TYPE as channelCorpType,
cc.company_code  as companyCode,
cc.company_name_cn as companyName
from T_CHANNEL_PRODUCT_REF cp,
     t_channel_info   ci,
     t_channel_corp   cc,
     t_channel_busi_model bu
where cp.channel_id = ci.id and ci.corp_id = cc.company_code and  cp.business_md_id = bu.id and cp.Spread_State <![CDATA[<>]]> 2 
	</select>

实现的效果是,将同packageid同channelid的数据放到同一个list中去。

因为已packageid同channelid分组，所以，虽然值需要获得list中数据，但是resultMap中叶需要将packageid和channelid加上去，否则没有任何效果。。。。，即上文中，红字部分一定要注意，不要搞丢了。

事实上分组的实现不是在数据库中实现，而是查出所有数据后，在ibatis的代码中进行的实现，所以，如果需要进行分页查询。。。那就只能ibatis分组处理后，查出所需数据，然后对所有数据在代码中分组了。悲催。。。

看了好几个帖子，搜索相关的实现，好多贴中groupby的resultMap中，都没有分组的那个数据的property，试了几次才发现，应该是现在这样的。

ibatis 的 GroupBy属性的使用

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