MySQl的group by 与排序

SELECT * FROM vrv_paw_reportlog WHERE TYPE IN(1001,1002)  GROUP BY pcInfoId DESC

SELECT * FROM vrv_paw_reportlog WHERE TYPE IN(1001,1002)  GROUP BY pcInfoId ORDER BY TIME DESC

通过对比发现：

“GROUP BY pcInfoId DESC” 是在分组后组内进行排序

“GROUP BY pcInfoId ORDER BY TIME DESC”是在分组后对产生的结果进行排序，是组外的