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這篇“MyBatis如何實(shí)現(xiàn)多表聯(lián)合查詢r(jià)esultType的返回值”文章的知識(shí)點(diǎn)大部分人都不太理解,所以小編給大家總結(jié)了以下內(nèi)容,內(nèi)容詳細(xì),步驟清晰,具有一定的借鑒價(jià)值,希望大家閱讀完這篇文章能有所收獲,下面我們一起來(lái)看看這篇“MyBatis如何實(shí)現(xiàn)多表聯(lián)合查詢r(jià)esultType的返回值”文章吧。
<select id="queryCarIdList" resultType="long"> select id from t_car_car </select>
<select id="queryDept" resultType="string"> SELECT deptname FROM t_car_run where deptid = #{deptid} GROUP BY deptname </select>
返回的類(lèi)型是實(shí)體類(lèi),因?yàn)椴樵兘Y(jié)果數(shù)據(jù)均為實(shí)體類(lèi)中字段的數(shù)據(jù)
<select id="queryNumber" resultType="io.renren.modules.generator.entity.TCarRunEntity"> select number from t_car_car where id = #{carid} </select>
返回的類(lèi)型是實(shí)體類(lèi),因?yàn)椴樵兘Y(jié)果數(shù)據(jù)均為實(shí)體類(lèi)中字段的數(shù)據(jù)
<select id="queryCar" resultType="io.renren.modules.generator.entity.TCarCarEntity"> select * from t_car_car </select>
t_car_car
t_car_driver
t_car_cardriver
t_car_cardriver存放的兩個(gè)字段分別是t_car_car和t_car_driver的主鍵id
1.resultType的返回類(lèi)型是java.util.Map
返回得到的是List中存放的所有數(shù)據(jù)
<select id="queryDriver" resultType="java.util.Map"> select driverid from t_car_cardriver where carid = #{id} </select>
2.新建一個(gè)實(shí)體類(lèi)
里面存放的是查詢結(jié)果里需要的字段名
// TCarCarDriver private Long carid; private Long driverid;
返回類(lèi)型為該實(shí)體類(lèi)
<select id="queryDriver" resultType="TCarCarDriver"> select driverid from t_car_cardriver where carid = #{id} </select>
多層集合嵌套返回結(jié)果用resultMap,collection中再次使用resultMap
<resultMap id="chainVo" type="com.suncnpap.intelligentqa.vo.ChainVo"> <id column="cid" property="id"/> <result column="access_key" property="accessKey"/> <result column="secret_key" property="secretKey"/> <result column="outer_chain_name" property="outerChainName"/> <result column="outer_chain_document" property="outerChainDocument"/> <collection property="intentionVos" ofType="com.suncnpap.intelligentqa.vo.ChainIntentionVo" resultMap="intentionVos"/> </resultMap> <resultMap id="intentionVos" type="com.suncnpap.intelligentqa.vo.ChainIntentionVo"> <id column="iid" property="id"/> <result column="intention_name" property="intentionName"/> <collection property="questionVoList" ofType="com.suncnpap.intelligentqa.vo.MultiQuestionVo"> <id column="qid" property="id"/> <result column="question" property="question"/> </collection> <collection property="wordVos" ofType="com.suncnpap.intelligentqa.vo.ChainIntentionWordVo"> <id column="wid" property="id"/> <result column="word_slot" property="wordSlot"/> <result column="word_slot_miss_question" property="wordSlotMissQuestion"/> <result column="entity_type_ids" property="entityTypeIds"/> </collection> </resultMap> <select id="detail" resultMap="chainVo"> select tc.id as tid, tci.id as iid, tciw.id as wid, tmq.id as qid, access_key, secret_key, outer_chain_name, outer_chain_document, intention_name, question, word_slot, word_slot_miss_question, entity_type_ids from t_chain tc left join t_chain_intention tci on tc.id = tci.chain_id left join t_chain_intention_word tciw on tci.id = tciw.intention_id left join t_multi_question tmq on tci.id = tmq.parent_id where tc.id = #{id} and tc.deleted = 0 </select>
以上就是關(guān)于“MyBatis如何實(shí)現(xiàn)多表聯(lián)合查詢r(jià)esultType的返回值”這篇文章的內(nèi)容,相信大家都有了一定的了解,希望小編分享的內(nèi)容對(duì)大家有幫助,若想了解更多相關(guān)的知識(shí)內(nèi)容,請(qǐng)關(guān)注億速云行業(yè)資訊頻道。
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