带有 DATEADD() 逻辑的 LINQ 查询的 SELECT 语句中的 IF ELSE 条件

Question

更新： 我正在尝试使用 LINQ 将以下 SQL 逻辑转换为 C# 代码，我对如何处理 SELECT 语句和 DATEADD 函数中的 CASE WHEN 和 ELSE 条件几乎没有混淆。

WITH tmp AS (
    SELECT  
    ID, 
    StartDate AS ReportingDate, 
    IncrementYears, 
    IncrementMonths,
     IncrementDays,
      DATEADD(YEAR, 1, GETDATE()) AS EndDate
    FROM    TransactionDetailDateFrequency
    UNION ALL
    SELECT  tmp.ID,
            CASE WHEN 
            tmp.IncrementDays > 0 
            THEN DATEADD(YEAR,tmp.IncrementYears,DATEADD(MONTH,tmp.IncrementMonths,DATEADD(DAY,tmp.IncrementDays,tmp.ReportingDate)))
            ELSE 
            EOMONTH(DATEADD(YEAR,tmp.IncrementYears,DATEADD(MONTH,tmp.IncrementMonths,tmp.ReportingDate))) 
            END AS ReportingDate,
            tmp.IncrementYears, 
            tmp.IncrementMonths, 
            tmp.IncrementDays, 
            tmp.EndDate
    FROM    tmp
    WHERE   tmp.ReportingDate < tmp.EndDate) 

    select * from tmp
    OPTION (MAXRECURSION 0)

到目前为止，我已经转换了它，

var calculatedDate = DateTime.Now.AddYears(1);

        var items = (from TDD in IngestionHubContext.TransactionDetailDateFrequency
                     select new { TDD.Id, ReportingDate = TDD.StartDate, TDD.IncrementYears, TDD.IncrementMonths, TDD.IncrementDays, EndDate = calculatedDate });

        var Temp = items.Concat(from T in items
                                where T.ReportingDate < T.EndDate
                                select new
                                {
                                    T.Id,
                                    ReportingDate = T.IncrementDays > 0 ? T.ReportingDate.Value.AddYears(T.IncrementYears.Value).AddMonths(T.IncrementMonths.Value).AddDays(T.IncrementDays.Value):
                                     T.ReportingDate.Value.AddYears(T.IncrementYears.Value).AddMonths(T.IncrementMonths.Value),
                                    T.IncrementYears,
                                    T.IncrementMonths,
                                    T.IncrementDays,
                                    T.EndDate
                                });

有人可以指导我如何在 LINQ 中的 c# 中实现 EOMONTH() 逻辑

更新：我在上面添加了 Linq 查询，但在 items.Concat 处出现错误 - '不包含 concat 的定义和最佳扩展方法重载'ParallelEnumerable.Concat''：已解决

还有在 C# 中获得等效 EOMONTH 的任何提示

感谢任何帮助。

提前致谢。

Answer 1

您想要做的是更容易理解如何使用稍微不同的语句格式来执行您的 CASE。你只需要使用ternary operator。使用DATEADD 函数需要一些本机函数built into Entity Framework >= 6.0。

(from TDD in IngestionHubContext.TransactionDetailDateFrequency
select new { 
    TDD.Id, 
    CalculatedDate = TDD.IncrementDays > 0 ?
        DbFunctions.AddYears(
            DbFunctions.AddMonths(
                DbFunctions.AddDays(TDD.ReportingDate, 
                                    TDD.IncrementDays), 
                TDD.IncrementMonths), 
            TDD.IncrementYears) :
        DbFunctions.AddYears(
            DbFunctions.AddMonths(TDD.ReportingDate,
                                  TDD.IncrementMonths),
            TDD.IncrementYears),
    ReportingDate = TDD.StartDate, 
    TDD.IncrementYears, 
    TDD.IncrementMonths, 
    TDD.IncrementDays, 
    EndDate = calculatedDate 
});