Mybatis关联查询遇到的坑-无主键的关联数据去重问题

<resultMap id="DeviceTypeResultMap" type="DeviceInfo">
    <!-- 有没有查询主键，返回的数据都是正确数据 -->
    <!--<id column="device_id" property="deviceId" jdbcType="BIGINT"></id>-->
    <result column="device_type_name" property="deviceTypeName" jdbcType="VARCHAR" />
    <result column="device_type_id" property="deviceTypeId" jdbcType="INTEGER" />
</resultMap>

public class DeviceInfo implements Serializable {
    private Long deviceId;
    private Integer deviceTypeId;
    private String deviceTypeName;
    private RawData rawData;
    ……
}

<resultMap id="BaseResultMap"
    type="DeviceInfo">
    <id column="device_id" property="deviceId" jdbcType="BIGINT"></id>
    <result column="mac" property="mac" jdbcType="VARCHAR" />
    <result column="device_type_id" property="deviceTypeId" jdbcType="BIGINT" />
    <association property="rawData"
        javaType="RawData">
        <id column="device_id" property="deviceId" />
        <result column="data_time" property="dataTime" jdbcType="TIMESTAMP" />
        <result column="battery_power" property="batteryPower"
            jdbcType="TINYINT" />
    </association>
</resultMap>

<select id="getDeviceTypeList" parameterType="DeviceInfo" resultMap="BaseResultMap">
    select device_type_id,device_type_name FROM tb_device_info group by device_type_id order by null
</select>