访问IIF表达式转换为SQL

Question

我继承了下面的IIF语句，试图将其转换为SQL Where条件的Access查询。 我已经玩了几天，但无法获得相同的结果。 任何帮助，将不胜感激。

访问

WHERE (((IIf([EFFDATE]-[MATDATE]<>[PDU_DAYS]-1 And [Calc_Type]="Cycles",IIf([PDU_DAYS] Between [30DayDQMin]+1 And [89DayDQMax]+1,"Yes","No"),IIf([PDU_DAYS] Between 31 And 90,"Yes","No")))="Yes"));

对于SQL代码，我一直在尝试各种布尔语句，例如以下语句。 我也尝试过建立一些案例逻辑。 到目前为止没有运气。

([EffDATE]-[MatDate] <> [PDU_Days]-1 and CalcType = 'Cycles' and PDU_Days Between [30DayDQMin]+1 and [89DayDQMax]+1 or PDU_Days Between 31 and 90)

Answer 1

您应该成功使用以下几种CASE WHEN x THEN a ELSE b END指令：

WHERE
CASE WHEN (([EFFDATE]-[MATDATE]<>[PDU_DAYS]-1) And ([Calc_Type]='Cycles')) THEN
    CASE WHEN (([PDU_DAYS] Between [30DayDQMin]+1) And ([89DayDQMax]+1))
        THEN 'Yes' ELSE 'No' END
ELSE 
     CASE WHEN ([PDU_DAYS] Between 31 And 90) THEN 'Yes' ELSE 'No' END
END 

= 'Yes'

注意T-SQL单引号样式！

Answer 2

这是等效的SQL-Server语法：

(
    CASE WHEN ([EFFDATE]-[MATDATE] <> [PDU_DAYS]-1 AND [Calc_Type]= 'Cycles') THEN
        CASE WHEN ([PDU_DAYS] BETWEEN [30DayDQMin]+1 AND [89DayDQMax]+1) THEN 'Yes' ELSE 'No' END
    ELSE
        CASE WHEN [PDU_DAYS] BETWEEN 31 AND 90 THEN 'Yes' ELSE 'No' END
    END
) = 'yes'

如果[MATDATE]和[EFFDATE]是datetime字段，则：

(
    CASE WHEN (DATEDIFF(dd,[MATDATE],[EFFDATE]) <> [PDU_DAYS]-1 AND [Calc_Type]= 'Cycles') THEN
        CASE WHEN ([PDU_DAYS] BETWEEN [30DayDQMin]+1 AND [89DayDQMax]+1) THEN 'Yes' ELSE 'No' END
    ELSE
        CASE WHEN [PDU_DAYS] BETWEEN 31 AND 90 THEN 'Yes' ELSE 'No' END
    END
) = 'Yes'

Answer 3

您确实不需要所有条件卷积，这应该产生相同的结果：

WHERE ([EFFDATE]-[MATDATE]<>[PDU_DAYS]-1 
       AND [Calc_Type]="Cycles" 
       AND ([PDU_DAYS] BETWEEN [30DayDQMin]+1 AND [89DayDQMax]+1)
      )
      OR ([PDU_DAYS] Between 31 And 90)