Mybatis 将数据库中查出的记录，一对多返回，即分组，然后返回每个组的所有数据

需求是一个pid下面会带多个子id，前端传一组pid集合，返回根据pid分组的所有子id及子id下的信息

  <select id="listBvsCustByParentMemberIds" resultMap="sellerCodeMap">
    select
    b.id as custMemberId,
    bvs.cust_code,
    mb.id as parentMemberId
    from member_base mb inner join bvs_parent_customer_info bvs on mb.seller_code = bvs.parent_code
    left join member_base  b on b.seller_code = bvs.cust_code
    where bvs.parent_code != bvs.cust_code and
    mb.id in
    <foreach collection="memberIds" item="memberId" open="(" separator="," close=")">
      #{memberId}
    </foreach>
  </select>

  <resultMap id="sellerCodeMap"
             type="com.yilihuo.cloud.service.user.dto.api.membercompany.ListBvsCustByParentMemberIdsResultDto">
    <result property="parentMemberId" column="parentMemberId"/>
    <collection property="childMemberInfos" ofType="com.yilihuo.cloud.service.user.dto.api.membercompany.ChildMemberInfoDto">
      <result property="custMemberId" column="custMemberId"></result>
      <result property="sellerCode" column="cust_code"></result>
    </collection>
  </resultMap>

通过<collection>标签，将parentMemberId 相同的记录存到ChildMemberInfoDto 里。然后返回，不需要其它逻辑.在一个就是需要

resultMap="sellerCodeMap"> 这个标签，将数据库查询的记录与出参返回值进行一个映射。

 出参样式