按组排序

Question

是否有一种有效的方式来执行订单和分组,以便从每个组(从订单中)获取特定项目.

//This is the best way i have come up with.
SELECT D.*
FROM (
    SELECT *
    FROM devices
    ORDER BY time
) AS D
GROUP BY D.location

Answer 1

SELECT *
FROM devices
GROUP BY D.location
ORDER BY time --ASC or DESC default is ASC i believe

不需要子查询