mybatis 多表查询

 <resultMap type="com.juncdt.mips.content.entity.PlaylistEntity" id="playlistMap2">
        <result property="id" column="id"/>
        <result property="createTime" column="create_time"/>
        <result property="updateTime" column="update_time"/>
        <result property="comapnyId" column="comapny_id"/>
        <result property="title" column="title"/>
        <result property="type" column="type"/>
        <result property="invalid" column="invalid"/>
        <result property="totalDuration" column="total_duration"/>
        <collection  property="playlistDetailEntities"   javaType="java.util.List"   resultMap="playlistDetailMap" />
    </resultMap>

<resultMap type="com.juncdt.mips.content.entity.PlaylistDetailEntity" id="playlistDetailMap">
        <result property="id" column="playDetailId"/>
        <result property="playlistId" column="playlist_id"/>
        <result property="type" column="playDetailType"/>
        <result property="materialId" column="material_id"/>
        <result property="duration" column="duration"/>
        <result property="sortNum" column="sort_num"/>
    </resultMap>

<select id="selectlistInfo" parameterType="com.juncdt.common.page.MyPage" resultMap="playlistMap2">
                  SELECT
            s1.id,
            s1.create_time,
            s1.update_time,
            s1.comapny_id,
            s1.title,
            s1.type,
            s1.invalid,
            s1.total_duration,
            s2.playlist_id,
            s2.id playDetailId,
            s2.type playDetailType,
            s2.material_id,
            s2.duration,
            s2.sort_num
        FROM
            c_playlist AS s1
            LEFT JOIN c_playlist_detail AS s2 ON s1.id = s2.playlist_id
        WHERE

            s1.invalid =0
    </select>

主要是

    <collection  property="playlistDetailEntities"   javaType="java.util.List"   resultMap="playlistDetailMap" />
    </resultMap>