Linq使用与另一个表不匹配的记录优化查询

Question

我正在进行以下查询，该查询从具有不应存在于另一个表中的记录的表中提取数据。

查询工作正常，但耗时太多＆amp;表现受到极大影响。

我可以对此查询进行哪些更改以获得更好的性能，还是应该以其他方式执行此操作？

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

您也可以尝试使用join而不是内部查询...您可以根据需要使用此类更改...

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();