LINQ到实体查询（1到很多）

Question

我需要对实体建立查询以获取记录，包括：

• AssetWeapon ，
• PersonOut
• IsIn = True的记录数
• IsIn = False的记录数，
• StartTime月份的名称，

记录应按AssetWeapon分组

替代文字http://www.freeimagehosting.net/uploads/4fee01b48c.png

Answer 1

也许本文可以为您提供帮助：

http://msdn.microsoft.com/en-us/vcsharp/aa336746.aspx

看投影算子..

Answer 2

这是我终于得到的：

var query = from ta in db.Transactions_Assets.Include("Transaction")
                        let items = new
                        {
                            Weapon = ta.AssetWeapon,
                            Month = ta.Transaction.StartTime.Value.Month,
                            IsIn = ta.IsIn 
                        }
                        group items by items.Weapon into g
                        select new { 
                            Weapon = g.Key,
                            MonthlyFlow = from m in g 
                                    group m by m.Month into mg
                                    select new { Month = mg.Key, 
                                                 Ins = mg.Count( x => x.IsIn == true),
                                                 outs = mg.Count(x => x.IsIn == false)
                                    }
                        };