Linq優化與記錄不匹配的查詢從另一個表

Question

我有以下查詢從表中提取數據與不應存在於另一個表中的記錄。

該查詢工作正常，但需要太多時間&性能受到極大影響。

我可以對此查詢進行哪些更改以獲得更好的性能，還是應該以另一種方式進行此操作？

var data = (from A in ctx.tblMachine 
where 
    A.CompanyId == companyId && 
    A.InOutDate >= tempDt && 
    A.InOutDate <= toDate && 
!(from B in ctx.tblEntry 
where 
    B.CompanyId == companyId && 
    A.EmployeeId == B.EmployeeId && 
    A.InOutDate == B.EntryDate && 
    B.EntryMethod == "M" 
select new 
{ 
    B.EmployeeId 
}).Contains(new { EmployeeId = A.EmployeeId }) 
orderby 
A.EmployeeId, A.InOutDate select new 
{ 
    A.EmployeeId, 
    A.InOutDate, 
    A.InOutFlag, 
    A.InOutTime 
}).ToList(); 

Answer 1

您可以也湊，而不是內部查詢嘗試......你可以用這個方法使變化根據自己的需要..

var data = (from A in ctx.tblMachine 
     join B in ctx.tblEntry on A.EmployeeId == B.EmployeeId && 
            A.InOutDate == B.EntryDate && 
            B.CompanyId == companyId && 
            B.EntryMethod == "M" 
     where 
       A.CompanyId == companyId && 
       A.InOutDate >= tempDt && 
       A.InOutDate <= toDate && 
       !(B.EmployeeId).Contains(new { EmployeeId = A.EmployeeId }) 
     orderby 
     A.EmployeeId, A.InOutDate 
     select new 
     { 
      A.EmployeeId, 
      A.InOutDate, 
      A.InOutFlag, 
      A.InOutTime 
     }).ToList();