技術標籤：Mybatis系列踩坑記技術雜記mysqlmybatis資料庫

1，通過子查詢的方式即可解決pageHelper分頁中少取資料問題

  <resultMap id="BaseResultMap" type="com.tcly.mall.vo.ums.UmsMomentsVO">
        <id column="id" jdbcType="BIGINT" property="id"/>
        <result column="
 
code" jdbcType="VARCHAR" property="code"/>
        <result column="type" jdbcType="INTEGER" property="type"/>
        <result column="open_id" jdbcType="VARCHAR" property="openId"/>
        <result column
 
="nickname" jdbcType="VARCHAR" property="nickname"/>
        <result column="personalized_signature" jdbcType="VARCHAR" property="personalizedSignature"/>
        <result column="OpenCode" jdbcType="VARCHAR" property
 
="openCode"/>
        <result column="MemberName" jdbcType="VARCHAR" property="memberName"/>
        <!--集合內查詢方式解決，column為上面的結果對應屬性-->
        <collection property="umsMomentsRelationVOS" ofType="com.tcly.mall.vo.ums.UmsMomentsRelationVO" column="id"
                    javaType="list"
                    select="selectMomentRelations">
        </collection>

    </resultMap>
        <!--子查詢對應的map-->

    <resultMap id="UmsMomentsRelationVOS" type="com.tcly.mall.vo.ums.UmsMomentsRelationVO">
        <id column="id" jdbcType="BIGINT" property="id"/>
        <result column="moment_id" jdbcType="BIGINT" property="momentId"/>
        <result column="relation_type" jdbcType="INTEGER" property="relationType"/>
        <result column="topic_id" jdbcType="BIGINT" property="topicId"/>
        <result column="topic_name" jdbcType="VARCHAR" property="topicName"/>
        <result column="file_url" jdbcType="VARCHAR" property="fileUrl"/>
        <result column="commodity_type" jdbcType="INTEGER" property="commodityType"/>
        <result column="commodity_name" jdbcType="VARCHAR" property="commodityName"/>
        <result column="commodity_pic" jdbcType="VARCHAR" property="commodityPic"/>
        <result column="commodity_price" jdbcType="DECIMAL" property="commodityPrice"/>
    </resultMap>
        <!--子查詢-->
    <select id="selectMomentRelations"
            resultType="com.tcly.mall.vo.ums.UmsMomentsRelationVO"
            resultMap="com.tcly.mall.dao.memberSource.UmsMomentsDao.UmsMomentsRelationVOS">
        select *
        from ums_moments_relation
        where moment_id = #{id}
    </select>

    
    <select id="page" resultMap="BaseResultMap" parameterType="com.tcly.mall.dto.param.MomentsParam">
        SELECT moments.*,
        u.new_name as username
        ,u.icon
        ,u.nickname
        ,u.personalized_signature
        ,u.OpenCode
        ,u.MemberName
        FROM ums_moments moments
        LEFT JOIN ums_member u ON moments.member_id = u.id
        <where>
            <if test="queryParam.postContent != null">
                AND moments.post_content LIKE CONCAT('%',#{queryParam.postContent},'%')
            </if>
            <if test="queryParam.companyId != null">
                AND moments.company_id = #{queryParam.companyId}
            </if>
            <if test="queryParam.startTime != null and queryParam.startTime != ''">
                AND DATE(moments.create_time) >= #{queryParam.startTime}
            </if>
            <if test="queryParam.endTime != null and queryParam.endTime != ''">
                AND DATE(moments.create_time) <![CDATA[ <= ]]> #{queryParam.endTime}
            </if>
            <if test="queryParam.username != null">
                AND u.username LIKE CONCAT('%',#{queryParam.username},'%')
            </if>
            AND moments.is_delete = 0
        </where>
    </select>

• 重點是這段程式碼，集合一定要這樣

<!--集合內查詢方式解決，column為上面的結果對應屬性-->
        <collection property="umsMomentsRelationVOS" ofType="com.tcly.mall.vo.ums.UmsMomentsRelationVO" column="id"
                    javaType="list"
                    select="selectMomentRelations">
        </collection>