c# - 将 SQL Rank() 转换为 LINQ 或替代方法

Question

我有下面的 SQL 语句，可以按预期/预期工作。但是我想将它翻译成 LINQ 语句(Lambda？？)，以便它适合我的 DAL 的其余部分。但是我看不出如何在 LINQ 中模拟 Rank()。

我将其张贴在这里的原因(可能有误)是想看看是否有人可以替代 Rank() 语句，以便我可以将其切换。或者，如果有一种方法可以在 LINQ 中表示 Rank()，我们也将不胜感激。

USE CMO

SELECT      vp.[PersonID] AS [PersonId]
            ,ce.[EnrollmentID]
            ,vp.[FirstName]
            ,vp.[LastName]
            ,ce.[EnrollmentDate]
            ,ce.[DisenrollmentDate]
            ,wh.WorkerCategory

FROM  [dbo].[vwPersonInfo] AS vp
            INNER JOIN 
            (
                  [dbo].[tblCMOEnrollment] AS ce
                  LEFT OUTER JOIN
                        (
                              SELECT   *
                                          ,RANK()OVER(PARTITION BY EnrollmentID ORDER BY CASE WHEN EndDate IS NULL THEN 1 ELSE 2 END, EndDate DESC, StartDate DESC) AS whrank 
                              FROM  [dbo].[tblWorkerHistory]
                              WHERE WorkerCategory = 2
                        ) AS wh 
                              ON ce.[EnrollmentID] = wh.[EnrollmentID] AND wh.whrank = 1
            ) 
                  ON vp.[PersonID] = ce.[ClientID]

WHERE (vp.LastName NOT IN ('Client','Orientation','Real','Training','Matrix','Second','Not'))
AND (
            (wh.[EndDate] <= GETDATE())
            OR wh.WorkerCategory IS NULL
      ) 
AND (
            (ce.[DisenrollmentDate] IS NULL) 
            OR (ce.[DisenrollmentDate] >= GetDate())
      )

Answer 1

这是一个示例，展示了我将如何在 Linq 中模拟 Rank():

var items = new[]
{
    new { Name = "1", Value = 2 },
    new { Name = "2", Value = 2 },
    new { Name = "3", Value = 1 },
    new { Name = "4", Value = 1 },
    new { Name = "5", Value = 3 },
    new { Name = "6", Value = 3 },
    new { Name = "7", Value = 4 },
};
  
var q = from s in items
    orderby s.Value descending
    select new 
    { 
        Name = s.Name, 
        Value = s.Value,
        Rank = (from o in items
                where o.Value > s.Value
                select o).Count() + 1 
    };

foreach(var item in q)
{
    Console.WriteLine($"Name: {item.Name} Value: {item.Value} Rank: {item.Rank}");
}

输出

Name: 7 Value: 4 Rank: 1
Name: 5 Value: 3 Rank: 2
Name: 6 Value: 3 Rank: 2
Name: 1 Value: 2 Rank: 4
Name: 2 Value: 2 Rank: 4
Name: 3 Value: 1 Rank: 6
Name: 4 Value: 1 Rank: 6