Join and Group By with LINQ to Entities

Good code:

var query = (from s in db.ForumStatsSet

where s.LogDate >= date1 && s.LogDate <= date2

group s by new {

s.Topic.topicID, s.Topic.subject,

s.Topic.datum, s.Topic.Forum.forumID,

s.Topic.Forum.forumName,

s.Topic.Forum.ForumGroup.name } into g

orderby g.Count() descending

select new TopicStatsData

{

TopicId = g.Key.topicID,

Count = g.Count(),

Subject = g.Key.subject,

ForumId = g.Key.forumID,

ForumName = g.Key.forumName,

ForumGroupName = g.Key.name

});

var query = (from fg in db.ForumGroupSet

from f in fg.Forums

from t in f.Topics

from s in t.ForumStats

where s.LogDate >= date1 && s.LogDate <= date2

group s by new { t.topicID,

t.subject,

t.datum,

f.forumID,

f.forumName,

fg.name } into g

orderby g.Count() descending

select new TopicStatsData

{

TopicId = g.Key.topicID,

Count = g.Count(),

Subject = g.Key.subject,

ForumId = g.Key.forumID,

ForumName = g.Key.forumName,

ForumGroupName = g.Key.name

});

转载于:https://www.cnblogs.com/jinzhao/archive/2011/09/09/2172743.html