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LINQ 按多个字段排序(orderby、thenby、Take) orderby 子句解析为 OrderBy()方法,orderby descending 子句解析为OrderBy Descending()方法: var racers = Formula1.GetChampions(). Where(r = > r.Country == "Brazil"). OrderByDescending(...

System.Linq 命名空间提供支持使用语言集成查询 (LINQ) 进行查询的类和接口 using + 命名空间名字,这样可以在程序中直接用命名空间中的类型,而不必指定类型的详细命名空间.

var q = from c in db.Customers where c.City == "London" select c 等价于SQL语句 select * from db.Customers c where c.City = "London" 然后把记录集赋给变量q foreach (var v in q) 表示记录集q里的每一条记录v要执行下马{}里的操作

string[] ids = (from DeductionBill in t_ds_DeductionBill where t_ds_DeductionBill .BillNumber.Equals(c.BillNumber)) .ToArray(); TotalWeight= (from Order in t_kd_Order where(item => ids.Contains(item.OrderID)) select Order.Total...

错误代码:var orders = db.Orders.Where(o => o.UserId == userid).Select(c => new Order { OrderId = c.OrderId, OrderDate = c.OrderDate, Total = c.Total, OrderDetails = db.OrderDetailss.Where(od => od.OrderId == c.OrderId).ToList(...

SQL:select * from A,B where A.cpID=B.cpID and A.cbID=B.cbID LINQ:var p = from t1 in a from t2 in b from t3 in c where t1.cpid equal t2.cpid and t1.cbid equal t3.cbid select new { t1, t2.cpid }

假设你上图表格数据为 DataTable dt,列分别为AA,BB,CC,DD var query = from p in dt.AsEnumerable() //分组 group p by new { t1 = p.Field("AA").ToString().Substring(0, p.Field("AA").ToString().Length - 2), t2 = p.Field("BB"), t3 = p....

你这查询有问题啊,b既不是分组又不是聚合函数啊 b应该也包含在分组中吧 var rows = db.c.GroupBy(acc => new { a = acc.a, b = acc.b}).Select(g => new { count = g.Key.a.Count(), b = g.Key.b });

var value=(from v in db.tbl select v.name).Distinct().ToList();

SumA = (from c in vSession.Linq() select c.a).Sum(); CountB = (from c in vSession.Linq() select c.b).Count(); ------解决方案-------------------- C# code//更改成这种形式 var query = from w in data.News select new { sum=data.News...

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