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使用Mybatis分页插件PageHelper时的分页问题

作者:互联网

使用Mybatis分页插件PageHelper时的分页问题

1对1查询,分页正常

1对多查询,如使用左右连接查询则会导致结果的总记录条数,子记录条数会叠加到主记录条数,导致数据不对称。

总结:使用mybatis时,在一对多的查询并且需要分页的时候需要使用子查询形式。

  1) 主记录的resultMap
  <resultMap id="artWorkMap" type="com.slipstream.wrt.wrtws.core.entity.Artwork"> <id column="id" jdbcType="VARCHAR" property="id"></id> <result column="commited" jdbcType="VARCHAR" property="commited"></result> <association property="user"> <id column="u_id" jdbcType="VARCHAR" property="id"></id> <result column="u_username" jdbcType="VARCHAR" property="username"></result> </association> <association property="template" resultMap="templateRigMap"> </association> <collection property="materialCompositions" ofType="com.slipstream.wrt.wrtws.core.entity.MaterialComposition"
select="selectMaterialCompositions" ### 关联的子查询
          column="id"> ### 传主记录的列名的参数值 </collection> </resultMap>

  2) 子记录的ResultMap,依次为 "1对1" 的与 "1对多" 的
    <resultMap id="templateRigMap" type="com.slipstream.wrt.wrtws.core.entity.Template">
    <id column="bt_id" jdbcType="VARCHAR" property="id"></id>
    <result column="bt_template_name" jdbcType="VARCHAR" property="templateName"></result>
     <result column="bt_deleted" jdbcType="BIT" property="deleted"></result>
     <result column="bt_create_date" jdbcType="TIMESTAMP" property="createDate"></result>
    </resultMap>
    
    <resultMap id="materialCompositionsRigMap" type="com.slipstream.wrt.wrtws.core.entity.MaterialComposition">
     <id column="bmc_id" jdbcType="VARCHAR" property="id"></id>
     <result column="bmc_artwork_id" jdbcType="VARCHAR" property="artworkId"></result>
    </resultMap>
  
  3)主记录查询 (把一对一的查询放在一起,一对多的数据另写一条查询)
    <select id="selectAllOrInCompany" resultMap="artWorkMap">
    SELECT
     ba.*

     ,su.id "u_id"
     ,su.username "u_username"

     ,bc.id
    ,bc.company_no
     ,bc.update_date "c_update_date"

     ,bb.id "bb_id"
    ,bb.update_date "bb_update_date"

     ,bt.id "bt_id"
     ,bt.update_date "bt_update_date"

     from biz_artwork ba
     left join sys_user su on su.id = ba.user_id
     left join biz_company bc on bc.id = su.company_id
     left join base_brand bb on ba.brand_id = bb.id
     left join base_template bt on ba.template_id = bt.id
     where ba.deleted = 0
<choose>
<when test="companyNo !=null and companyNo != ''">
and ba.artwork_no like concat('', #{companyNo}, '%')
</when>
<otherwise>
and ba.commited = 1
</otherwise>
</choose>
<if test="keywords !=null and keywords.length() > 0">
and (
ba.artwork_no like concat('%', #{keywords}, '%')
or su.username like concat('%', #{keywords}, '%')
or bc.company_name like concat('%', #{keywords}, '%')
)</if>
order by ba.update_date desc
</select>
  
  4)子记录查询
    <select id="selectMaterialCompositions" resultMap="materialCompositionsRigMap">
    select
       bmc.id "bmc_id"
       ,bmc.create_date "bmc_create_date"
       ,bmc.update_date "bmc_update_date"
    from biz_material_composition bmc
      where bmc.artwork_id = #{id} ### 接收主记录的列名的参数值
    </select>




 

标签:bmc,插件,分页,update,PageHelper,date,查询,id,ba
来源: https://www.cnblogs.com/erfsfj-dbc/p/11759784.html