//输出体重最大的同学，并要求最大体重得大于39，并按照体重大下，对分组结果进行排序。                    var result = from query in linq.Student                                 group query by query.ClassID into gS                                 where gS.Max
     
      (s => s.StudentWeigth) > 39                                 orderby gS.Max
      
       (s => s.StudentWeigth) descending                                 select new                                 {                                     ClassID = gS.Key,                                     MaxWeight = gS.Max
       
        (s => s.StudentWeigth)                                 };                    var result = from query in linq.Student                                group query by query.ClassID into gS                                                                 let mw = gS.Max
        
         (s => s.StudentWeigth)                                where mw > 39                                select new                                {                                    ClassID = gS.Key,                                    MaxWeight = mw                                };                    foreach (var item in result)                    {                        Response.Write(string.Format("classid = {0} studentmaxweight = {1}", item.ClassID, item.MaxWeight));                    }
        
       
      
     

 

//查询身高大于132并且体重大于30的Student，并按照StudentID升序排序，按照classID降序排序var query = from s in db.Students            where s.HeightInCm > 132 && s.WeightInKg > 30            orderby s.StudentID ascending, s.ClassID descending            select s;

 

//对Student表按照ClassID和Hometown两个字段进行分组，并输出每个班级中某个地方的学生数var query = from s in db.Students                        group s by new { s.ClassID, s.Hometown } into gS                        let cn = gS.Count
     
      ()                        select new                        {                            ClassID = gS.Key.ClassID,                            Hometown = gS.Key.Hometown,                            Count = cn                        };            foreach (var item in query)            {                Console.WriteLine("class id = {0} hometown {1} student count = {2}", item.ClassID, item.Hometown,item.Count);            }
     

 

//在上面的基础上加一点点需求，要求分组后的结果按照count排序var query = from s in db.Students            group s by new { s.ClassID, s.Hometown } into gS            let cn = gS.Count
     
      ()            orderby cn descending            select new            {                ClassID = gS.Key.ClassID,                Hometown = gS.Key.Hometown,                Count = cn            };