<resultMap id="DeviceTypeResultMap" type="DeviceInfo">
?? ?<!-- 有沒有查詢主鍵，返回的數(shù)據(jù)都是正確數(shù)據(jù) -->
?? ?<!--<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>

解決方法2

如果你的查詢不需要關聯(lián)數(shù)據(jù)，但是懶的再寫resultMap，那么SQL的查詢字段一定要加上主表的主鍵

例子：

DeviceInfo

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

DeviceInfo 關聯(lián)查詢 RawData 返回的 resultMap

<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>

根據(jù) device_type_id 分組查詢 device_type_id 和 device_type_name

<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>