如何在LINQ查询中使用GROUP BY获取MAX行？

Question

我正在寻找一种在LINQ中匹配以下SQL查询的方法。Select max(uid) as uid, Serial_Number from Table Group BY Serial_Number真的在这方面寻求一些帮助。上面的查询由于Group By语法而获得每个序列号的最大uid 。

Answer 1

    using (DataContext dc = new DataContext())

        {

            var q = from t in dc.TableTests

                    group t by t.SerialNumber

                        into g

                        select new

                        {

                            SerialNumber = g.Key,

                            uid = (from t2 in g select t2.uid).Max()

                        };

        }

Answer 2

var q = from s in db.Serials

        group s by s.Serial_Number into g

        select new {Serial_Number = g.Key, MaxUid = g.Max(s => s.uid) }

Answer 3

以方法链形式：

db.Serials.GroupBy(i => i.Serial_Number).Select(g => new

    {

        Serial_Number = g.Key,

        uid = g.Max(row => row.uid)

    });