diff --git a/internal/dao/sensor.go b/internal/dao/sensor.go
index b5067c5..77a299f 100644
--- a/internal/dao/sensor.go
+++ b/internal/dao/sensor.go
@@ -64,12 +64,7 @@ func (dao *SensorDAO) GetAggregatedData(start, end time.Time, interval string) (
 	// 构建通用查询
 	query := `
 		SELECT 
-			DATE_FORMAT(
-				FROM_UNIXTIME(
-					FLOOR(UNIX_TIMESTAMP(timestamp)/?)*?
-				),
-				?
-			) as ts,
+			MIN(timestamp) as ts,
 			ROUND(AVG(temperature)/10, 1) as avg_temp,
 			MAX(rainfall) - MIN(rainfall) as rainfall,
 			ROUND(AVG(humidity)/10, 1) as avg_humidity,
@@ -83,8 +78,6 @@ func (dao *SensorDAO) GetAggregatedData(start, end time.Time, interval string) (
 	// 执行查询
 	rows, err := dao.db.Query(
 		query,
-		intervalSeconds, intervalSeconds, // 用于FROM_UNIXTIME参数
-		timeFormat, // DATE_FORMAT格式
 		start, end, // 时间范围
 		intervalSeconds, // GROUP BY参数
 	)