LINQ для RANK() и случай, когда в VB.NET

Question

Я извиняюсь, если подобный вопрос уже задавали в VB.Net для RANK() и СЛУЧАЙ, КОГДА.

У меня есть две таблицы. Сценарий с необходимыми столбцами ниже:

Таблица 1:

SELECT S.* INTO dbo.LoanHeader 
FROM 
(
    SELECT 1 LoanHeaderId, 1234 LoanNumber, GETDATE() EffectiveOn 
    UNION ALL 
    SELECT 2 LoanHeaderId, 2234 LoanNumber, GETDATE() EffectiveOn 
    UNION ALL 
    SELECT 3 LoanHeaderId, 3234 LoanNumber, GETDATE() EffectiveOn 
)S 

Таблица 2:

SELECT S.* INTO dbo.LoanHeaderHistory 
FROM 
(
    SELECT 1 LoanHeaderId, 1 NewValue, 'LoanReviewStatusId' ColumnName, DATEADD(DD, -3, GETDATE()) EnteredDate 
    UNION ALL 
    SELECT 1 LoanHeaderId, 2 NewValue, 'LoanReviewStatusId' ColumnName, DATEADD(DD, -2, GETDATE()) EnteredDate 
    UNION ALL 
    SELECT 1 LoanHeaderId, 3 NewValue, 'LoanReviewStatusId' ColumnName, DATEADD(DD, -1, GETDATE()) EnteredDate 
    UNION ALL 
    SELECT 1 LoanHeaderId, 1 NewValue, 'LoanReviewStatusId' ColumnName, GETDATE() EnteredDate 
)S 

Я хотел бы написать LINQ заявление в VB.Net в в SQL ниже. Существуют и другие таблицы, и если я начну упоминать, почему мне это нужно, это займет слишком много времени. Но намерение состоит в том, чтобы использовать одну из дат, основанных на NewValue в критериях:

SELECT 
    LH.LoanHeaderId, 
    LHH.NewValue, 
    LHH.EnteredDate 
FROM dbo.LoanHeader LH 
LEFT JOIN 
(
    SELECT 
     LoanHeaderId, 
     NewValue, 
     EnteredDate, 
     RANK() OVER (PARTITION BY LoanHeaderId ORDER BY EnteredDate DESC) HRank 
    FROM dbo.LoanHeaderHistory 
    WHERE ColumnName = 'LoanReviewStatusId' 
)LHH ON LHH.LoanHeaderId = LH.LoanHeaderId AND LHH.HRank = 1 
WHERE CASE WHEN ISNULL(LHH.NewValue, 1) IN (2, 3) THEN LHH.EnteredDate ELSE LH.EffectiveOn END >= LH.EffectiveOn 

Я начал делать это таким образом:

Dim columnName = "LoanReviewStatusId" 
Dim query = (From lh In e.LoanHeaderEntities_ 
      From lhh In e.LoanHeaderHistoryEntities.OrderByDescending(Function(i) i.EnteredDate).Where(Function(i) lh.LoanHeaderId = i.LoanHeaderId AndAlso i.ColumnName = columnName).DefaultIfEmpty() _ 
      Select New With{ _ 
        lh.LoanHeaderId, _ 
        lhh.NewValue, _ 
        lhh.EnteredDate _ 
        }) 
query = query.Where(Function(i) If(Not IsNothing(i.LoanReviewStatusId) AndAlso (i.LoanReviewStatusId = 2 Or i.LoanReviewStatusId = 3), i.LoanStatusChangedDate, i.EffectiveOn) >= i.EffectiveOn) 
Return query.ToList() 

Answer 1

Ха! Я сделал это. Я нашел полезную информацию от here.

Код VB.Net является

Dim query = (From lh In e.LoanHeaderEntities _ 
     From lhhGrp In e.LoanHeaderHistoryEntities.Where(Function(i) i.ColumnName = colName And i.LoanHeaderId = lh.LoanHeaderId) _ 
     .OrderByDescending(Function(i) i.EnteredDate) _ 
     .Take(1) _ 
     .DefaultIfEmpty() _  
     Select New HeaderInfo With {_ 
      .LoanHeaderId = lh.LoanHeaderId, _    
      .EffectiveOn = lh.EffectiveOn, _ 
      .LoanStatusChangedDate = lhhGrp.EnteredDate, _ 
      .LoanReviewStatusId = lhhGrp.NewValue _ 
      }) 
'Additional condition for CASE WHEN 
If (isActive) Then 
    query = query.Where(Function(i) If(i.LoanReviewStatusId = LoanReviewStatus.Final Or i.LoanReviewStatusId = LoanReviewStatus.Completed, i.LoanStatusChangedDate, i.EffectiveOn) >= i.EffectiveOn) 
End If 
Return query.ToList() 

Я не мог удержаться от смеха, когда я увидел запрос он выполняет за кулисами. Проверьте приведенную ниже инструкцию CASE WHEN. Я проигнорировал ISNULL, потому что мое поле NOT NULL.

SELECT 
    [Extent1].LoanHeaderId, 
    [Limit1].NewValue, 
    [Limit1].EnteredDate 
FROM [dbo].[LoanHeader] AS [Extent1] 
OUTER APPLY 
(
    SELECT TOP (1) 
     [Project1].[LoanHeaderId] AS [LoanHeaderId], 
     [Project1].[NewValue] AS [NewValue], 
     [Project1].[EnteredDate] AS [EnteredDate] 
     FROM 
     (
      SELECT 
       [Extent2].[LoanHeaderId] AS [LoanHeaderId], 
       [Extent2].[NewValue] AS [NewValue], 
       [Extent2].[EnteredDate] AS [EnteredDate] 
      FROM [dbo].[LoanHeaderHistory] AS [Extent2] 
      WHERE ([Extent2].[ColumnName] = 'LoanReviewStatusId') 
      AND ([Extent2].[LoanHeaderId] = [Extent1].[LoanHeaderId]) 
     ) AS [Project1] 
     ORDER BY [Project1].[EnteredDate] DESC 
) AS [Limit1] 
WHERE ((CASE WHEN ((CASE WHEN (CASE WHEN ((3 = CAST([Limit1].[NewValue] AS int)) OR (2 = CAST([Limit1].[NewValue] AS int))) THEN cast(1 as bit) WHEN (NOT ((3 = CAST([Limit1].[NewValue] AS int)) OR (2 = CAST([Limit1].[NewValue] AS int)))) THEN cast(0 as bit) END IS NULL) THEN cast(0 as bit) WHEN ((3 = CAST([Limit1].[NewValue] AS int)) OR (2 = CAST([Limit1].[NewValue] AS int))) THEN cast(1 as bit) WHEN (NOT ((3 = CAST([Limit1].[NewValue] AS int)) OR (2 = CAST([Limit1].[NewValue] AS int)))) THEN cast(0 as bit) END) = 1) THEN CAST([Limit1].[EnteredDate] AS datetime) ELSE CAST([Extent1].[EffectiveOn] AS datetime) END) >= CAST([Extent1].[EffectiveOn] AS datetime)) 

Скажите, кто лучше в письменной форме, EF или меня?