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我有以下LINQ查询,我的目标是按年份和月份进行分组,并进行一些计算:我有一个ViewModel设置。我甚至不确定我的查询是否按预期工作,因为它不能编译。我得到这个错误多联接LINQ和按年份和月份组
System.NotSupportedException was unhandled by user code
HResult=-2146233067
Message=LINQ to Entities does not recognize the method 'System.Collections.Generic.IEnumerable`1[System.Int32] Range(Int32, Int32)' method, and this method cannot be translated into a store expression.
Source=EntityFramework
控制器代码
public ActionResult Summary(int? yr, int? mn, int? BkId)
{
var squery = SummaryYrMn(yr, mn, BkId);
return View(squery);
}
public IEnumerable SummaryYrMn()
{
var squery =
(from bk in db.Books
from year in Enumerable.Range(2010, DateTime.Today.Year)
from month in Enumerable.Range(1, 12)
let key = new { Year = year, Month = month }
//sold books
join tr in db.Transacts.Where(a => a.TransactTypeId==1 && a.Book.BookTypeId==1) on key
equals new{tr.TransactDate.Year, tr.TransactDate.Month} into s
//gifted books
join tr2 in db.Transacts.Where(a => a.TransactTypeId == 2 && a.Book.BookTypeId == 1) on key
equals new{tr2.TransactDate.Year, tr2.TransactDate.Month} into t
//gifted tracts books book type = tract
join tr3 in db.Transacts.Where(a => a.TransactTypeId == 2 && a.Book.BookTypeId == 2) on key
equals new { tr3.TransactDate.Year, tr3.TransactDate.Month } into u
select new SummaryViewModel
{
Year = year,
Month = month,
Gifted = (int?)t.Sum(c => c.TransactQty) ?? 0,
GSales = (int?)s.Sum(c => c.TransactQty) ?? 0,
GiftedTracts = (int?)u.Sum(c => c.TransactQty) ?? 0,
TotalGift = ((int?)t.Sum(c => c.Book.BookPrice))*((int?)s.Sum(c => c.TransactQty)??0),
TotalSale = ((int?)s.Sum(c => c.TransactPrice))*((int?)s.Sum(c => c.TransactQty)??0)
});
return squery.AsEnumerable();
}
如果不是[System.Linq.Enumerable](https://msdn.microsoft.com/en-us/library/system.linq.enumerable(v = vs.100).aspx)?尝试完全限定您的Enumerable.Range()。 –
仍然无法处理您的建议。你会以不同的方式做到这一点吗? – Diin
啊是的。我懂了。这是Linq的实体!是。为每个年份和月份创建一个变量,将Enumerable.Range赋值给它们。然后在你的linq中使用它们。 EF试图从你的linq生成sql,并且Enumerable.Range不是一个sql函数。那有意义吗? –