LinQ Group By

• 普通

var list = from s in db.mm_ShopMas
                       where s.IsStop == false
                       group s by s.SpaceId;

　　　Sql执行时会取全部数据。

• into

var list = from s in db.mm_ShopMas
                       where s.IsStop == false
                       group s by s.SpaceId into g
                       select g;

　　Sql执行时会取全部数据。

　　Select
　　

var list = from s in db.mm_ShopMas
                       where s.IsStop == false
                       group s by s.SpaceId into g
                       select new { g.Key,Total = g.Count()};

　　Sql执行的结果为汇总数据。

• 多列Group

var list = from s in db.mm_ShopMas
                       where s.IsStop == false
                       group s by new { s.SpaceId ,s.TradeId} into g
                       select new { g.Key, Total = g.Count() };

　　Sql执行结果为汇总数据。

　select new {g.Key.TradeId,g.Key.SpaceId,Tocal=g.Count()}

select new {g.Key,Tocal=g.Count()}

• 表达式

var list = from s in db.mm_ShopMas
                       where s.IsStop == false
                       group s by new { IdFirst = s.ShopId / 1000 } into g
                       select new { g.Key, Total = g.Count() };

Sql执行结果为汇总数据：