LINQ與MAX（），並加入

Question

有我使用

  var renewalQuery = from r in crnnsupContext.Renewals 
           from w in crnnsupContext.WorkPlaces 
           join p in crnnsupContext.ProvStates on p.ProvinceStateID equals r.EmployerProvState 
           where r.RegNumber == _username && r.PlaceOfWork == w.WorkID 
           select r; 

LINQ的聲明有一個r.RenewalYear，我想獲得最新的一年，所以我想是這樣

   var renewalQuery = from r in crnnsupContext.Renewals 
           group r by r.RenewalYear into g 
           from w in crnnsupContext.WorkPlaces 
           join p in crnnsupContext.ProvStates on p.ProvinceStateID equals r.EmployerProvState 
           where r.RegNumber == _username && r.PlaceOfWork == w.WorkID 
           select g.max(r.RenewalYear); 

顯然這不起作用，有沒有人知道這個正確的語法？非常感謝

Answer 1

選擇一年，然後在使用MAX（）：

var renewalQuery = (from r in crnnsupContext.Renewals 
           group r by r.RenewalYear into g 
           from w in crnnsupContext.WorkPlaces 
           join p in crnnsupContext.ProvStates on p.ProvinceStateID equals r.EmployerProvState 
           where r.RegNumber == _username && r.PlaceOfWork == w.WorkID 
           select r.RenewalYear).Max();