更新时间:2023-02-07 10:07:18
以下是使用Northwinds数据库的示例.这将为您提供预期的结果,但是SQL与您的示例不匹配.
Here is an example using the Northwinds database. This will get you the results that you are expecting but the SQL won't match your example.
using (var context = new NorthwindEntities())
{
DateTime volumn1Date = DateTime.Today.AddDays(-1);
DateTime volumn7Date = DateTime.Today.AddDays(-7);
DateTime volumn30Date = DateTime.Today.AddDays(-30);
var query = from o in context.Order_Details
group o by o.Product.ProductName into g
select new
{
ProductName = g.Key,
Volume1Day = g.Where(d => d.Order.OrderDate.Value <= volumn1Date)
// cast to Int32? because if no records are found the result will be a null
.Sum(d => (Int32?) d.Quantity),
Volume7Day = g.Where(d => d.Order.OrderDate.Value <= volumn7Date)
.Sum(d => (Int32?) d.Quantity),
Volume30Day = g.Where(d => d.Order.OrderDate.Value <= volumn30Date)
.Sum(d => (Int32?) d.Quantity)
};
var list = query.ToList();
}