SELECT c.SiteName,max(d.ScheduleTime),a.EnterpriseName,a.EnterpriseInfoID FROM EnterpriseInfo AS a
INNER JOIN EnterpriseSite AS b ON b.EnterpriseInfoID = a.EnterpriseInfoID
INNER JOIN SiteInfo AS c ON c.SiteInfoID = b.SiteInfoID
INNER JOIN ScheduleInfo AS d ON d.EnterpriseSiteID = b.EnterpriseSiteID
INNER JOIN EventType AS e ON e.EventTypeID = d.EventTypeID
GROUP BY c.SiteName,a.EnterpriseName,a.EnterpriseInfoID
//代码手打，提供思路参考
var query=from a in EnterpriseInfo
join b in EnterpriseSite on a.EnterpriseInfoID equals b.EnterpriseInfoID
join c in SiteInfo on b.SiteInfoID equals c.SiteInfoID
join d in ScheduleInfo on b.EnterpriseSiteID equals d.EnterpriseSiteID
join e in EventType on d.EventTypeID equals e.EventTypeID
group new{a,b,c,d} by new {c.SiteName,a.EnterpriseName,a.EnterpriseInfoID} into g
select new{g.Key.SiteName,ScheduleTime=g.Max(d=>ScheduleTime),g.Key.EnterpriseName,g.Key.EnterpriseInfoID};
