MS Access SQL Case When 表达式

Question

我正在尝试将代码块从 SQL Server Management Studio 转换为 Access 数据库，但我的 Case When 表达式遇到了一些问题。

我在下面的 Case When 中遗漏了什么以便它与 MS Access 查询兼容？

Case WHEN E.MemberStartDate <= "2018-01-01 AND E.MemberEndDate >= "2018-12-31" 
THEN "" 
WHEN "2018-01-01" <= E.MemberEndDate AND "2018-01-31" >= 
E.MemberStartDate THEN "X" ELSE "" END AS Cov1Jan

Answer 1

你错过了 MS-Access 不支持 case。所以：

switch(E.MemberStartDate <= "2018-01-01 AND E.MemberEndDate >= "2018-12-31", "", 
       "2018-01-01" <= E.MemberEndDate AND "2018-01-31" >= 
E.MemberStartDate, "X"
       1=1, "") AS Cov1Jan

Answer 2

尝试 IIf 和 octothorpes (#):

IIf(E.MemberStartDate <= #2018/01/01 AND E.MemberEndDate >= #2018/12/31#, 
    Null,
    IIf(#2018/01/01# <= E.MemberEndDate AND #2018/01/31# >= E.MemberStartDate, 
        "X", 
        Null)) AS Cov1Jan

MS Access SQL Case When 表达式

MS Access SQL Case When expression

tsql

ms-access

case-when