-- 取分组后的前几条
-- 分组获取所有分组后的数据（group_CONCAT函数），再用substring_index函数按照指定分隔符分割后获取前n个
-- 分组内的排序直接在group_concat内对该字段排序
select a.vehicle_no, SUBSTRING_INDEX(GROUP_CONCAT(a.gps_time order by a.gps_time desc),",",1) from (
select vehicle_no, gps_time from gps_vehicle_info
where vehicle_no in (‘KY6926‘, ‘DT6606‘, ‘RF7088‘)
ORDER BY gps_time desc
) a GROUP BY a.vehicle_no

sql