02.
Console.WriteLine("---------第一种写法");
03.
var TermAvgScore_1 = (from l in lst
04.
group l by new { Term = l.Term, Course = l.Course } into grouped
05.
orderby grouped.Average(m => m.Score) ascending
06.
orderby grouped.Key.Term descending
07.
select new { Term = grouped.Key.Term, Course = grouped.Key.Course, Scores = grouped.Average(m => m.Score) }).ToList();
08.
foreach (var l in TermAvgScore_1)
09.
{
10.
Console.WriteLine("学期:{0},课程{1},均分{2}", l.Term, l.Course, l.Scores);
11.
}
12.
Console.WriteLine("---------第二种写法");
13.
var TermAvgScore_2 = lst.GroupBy(m => new { Term = m.Term, Course = m.Course })
14.
.Select(k => new { Term = k.Key.Term, Course = k.Key.Course, Scores = k.Average(m => m.Score) })
15.
.OrderBy(l => l.Scores).OrderByDescending(l => l.Term);
16.
foreach (var l in TermAvgScore_2)
17.
{
18.
Console.WriteLine("学期:{0},课程{1},均分{2}", l.Term, l.Course, l.Scores);
19.
}
Linq中没有SQL中的Having语句，因此是采用where语句对Group后的结果过滤。
原文 : http://www.it165.net/pro/html/201301/4521.html