Question

I have this query in LINQ to Entities.

        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.Forum.forumName, s.Topic.datum, s.Topic.Forum.ForumGroup.name, s.Topic.Forum.forumID } into g                      orderby g.Count() descending                      select new TopicStatsData                      {                          TopicId = g.Key.topicID,                          Count = g.Count(),                          Subject = g.Key.subject,                          ForumGroupName = g.Key.name,                          ForumName = g.Key.forumName,                          ForumId = g.Key.forumID                      }); 

I know it is kind of an ‘Evil’ query but it is only used in a admin interface. But the SQL it generated is absolutely horrifying. Have a look at this baby.

 exec sp_executesql N'SELECT TOP (50)  [Project6].[C1] AS [C1],  [Project6].[TopicId] AS [TopicId],  [Project6].[C4] AS [C2],  [Project6].[subject] AS [subject],  [Project6].[name] AS [name],  [Project6].[forumName] AS [forumName],  [Project6].[C2] AS [C3] FROM ( SELECT      [Project5].[TopicId] AS [TopicId],      [Project5].[subject] AS [subject],      [Project5].[forumName] AS [forumName],      [Project5].[name] AS [name],      1 AS [C1],       CAST( [Project5].[forumID] AS int) AS [C2],      [Project5].[C1] AS [C3],      [Project5].[C2] AS [C4]     FROM ( SELECT          [Project4].[TopicId] AS [TopicId],          [Project4].[forumID] AS [forumID],          [Project4].[subject] AS [subject],          [Project4].[forumName] AS [forumName],          [Project4].[name] AS [name],          [Project4].[C1] AS [C1],          (SELECT              COUNT(cast(1 as bit)) AS [A1]             FROM        [dbo].[tForumStats] AS [Extent14]             LEFT OUTER JOIN [dbo].[tTopic] AS [Extent15] ON [Extent14].[TopicId] = [Extent15].[topicID]             LEFT OUTER JOIN [dbo].[tForum] AS [Extent16] ON [Extent15].[forumID] = [Extent16].[forumID]             LEFT OUTER JOIN [dbo].[tForum] AS [Extent17] ON [Extent15].[forumID] = [Extent17].[forumID]             LEFT OUTER JOIN [dbo].[tForum] AS [Extent18] ON [Extent15].[forumID] = [Extent18].[forumID]             LEFT OUTER JOIN [dbo].[tForumGroup] AS [Extent19] ON [Extent18].[forumGroupID] = [Extent19].[forumGroupID]             LEFT OUTER JOIN [dbo].[tForum] AS [Extent20] ON [Extent15].[forumID] = [Extent20].[forumID]             LEFT OUTER JOIN [dbo].[tForumGroup] AS [Extent21] ON [Extent20].[forumGroupID] = [Extent21].[forumGroupID]             WHERE ([Extent14].[LogDate] >= @p__linq__25) AND ([Extent14].[LogDate] = @p__linq__25) AND ([Extent6].[LogDate] = @p__linq__25) AND ([Extent1].[LogDate] 

I do not as anyone to explain that query but it would be great to get some tips on how to optimze the query so that it just do a simple regular join. Something like this works as fine if I write the SQL myself.

SELECT COUNT(*) AS NumberOfViews, s.topicid AS topicId, t.subject AS TopicSubject, g.[name] AS ForumGroupName, f.forumName AS ForumName  FROM tForumStats s join tTopic t on s.topicid = t.topicid join tForum f on f.forumid = t.forumid JOIN tForumGroup g ON f.forumGroupID = g.forumGroupID WHERE s.[LogDate] between @date1 AND @date2 group by s.topicid,  t.subject, f.Forumname, t.Datum, g.[name] order by count(*) desc 

Btw, i LOVE this site. Amazing design and usability! Hope it works good to get some help to 🙂

Answer 1

Instead of joining all tables in group by you can join the given tables by yourself. Can you try this;

from s in db.ForumStatsSet join t in db.Topics on t.TopicId == s.TopicId join f in db.Forums on f.ForumId == t.ForumId join fg in db.ForumGroups on fg.ForumGroupId == f.ForumGroupId where s.LogDate >= date1 && s.LogDate <=  group s by new { t.TopicId, t.subject, f.forumName, t.datum, fg.name, f.forumID } into g orderby g.Count() descending select new TopicStatsData {  TopicId = g.Key.topicID,  Count = g.Count(),  Subject = g.Key.subject,  ForumGroupName = g.Key.name,  ForumName = g.Key.forumName,  ForumId = g.Key.forumID  }); 

ps: There may be some errors, but logically it should be correct!