学步园

SELECT *

(SELECT COUNT(1) FROM vw_SiteAlarmData subTab WHERE vw_SiteAlarmData.siteid=subTab.siteid AND vw_SiteAlarmData.alarmid< subTab.alarmid )

 < 2

FROM vw_SiteAlarmData

ORDER BY siteid,alarmid

上例取的是每个siteid分类下两条数据