Question

已更新：我正在尝试使用LINQ将下面的SQL逻辑转换为C＃代码，并且我对如何处理SELECT语句和DATEADD功能中的CASE WHEN和ELSE条件几乎没有什么困惑。

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，我已经完成了转换

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的c＃中实现EOMONTH（）逻辑

已更新：我已在上面添加了Linq查询，但在项上出现错误。concat-'不包含concat的定义和最佳扩展方法重载'ParallelEnumerable.Concat <>''：已解决

任何获得C＃中的EOMONTH等效的技巧

感谢您的帮助。

谢谢。

Answer 1

您想要做的是更容易地理解如何以略有不同的语句格式执行CASE。您需要做的就是使用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 
});

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

1 个答案: