通过标识列名在SQL中使用MS Access代码

我在Microsfot Access中使用此代码并获得正确的结果：

SELECT tbl_Test.generate_query AS Query Name, 
       Sum(IIf([RecNum] Is Not Null,1,0)) AS Attempts, 
       Sum(IIf([Query_test]='Yes',1,0)) AS Successes, 
       Sum(IIf([Query_test]='No',1,0)) AS Failures, 
       [Successes] & "/" & [Attempts] AS SuccessProportion
       FROM tbl_Test
       GROUP BY tbl_Test.generate_query
       ORDER BY tbl_Test.generate_query;

当我将其转换为SQL时-

[successfulls]+'/'+[truments]按比例转换

失败，列名无效：

SELECT generate_query AS Query_Name, 
       sum(case when RecNum is NOT NULL then 1 else 0 end) AS Attempts, 
       sum(case when Query_test = 'Yes' then 1 else 0 end) AS Successes,
       sum(case when Query_test = 'No' then 1 else 0 end) AS Failures,
       [Successes]  + '/'  +  [Attempts] AS Proportion
       FROM tbl_TPF 
       GROUP BY generate_query 
       ORDER BY generate_query;

输出如下所示：

Query Name           Attempts        Successes      Failures    SuccessProportion
First Query             1               0               1               0/1
Second Query            1               0               1               0/1
Third Query             2               1               1               1/2
Fourth Query            1               1               0               1/1
Fifth Query             1               0               1               0/1
Sixth Query             1               0               1               0/1

---

我可以使用我在SQL中标识的列吗？

您使用的是什么RDBMS？请贴上标签。你必须使用你在BD上得到的实际列名。它无法知道它在access上是如何命名的（如果名称不同），我不明白你在说什么。我正在使用SQL Server Management Studio和Microsoft Visual Studio仅供参考，

sum（如果RecNum不为NULL，则为1 else 0 end）

是大量多余的代码。您可以简单地使用

COUNT（RecNum）

，类似地，您可以使用

COUNT（NULLIF（Query\u test，'No'））作为成功，使用NULLIF（Query\u test，'Yes'）作为失败来缩短代码。在您的例子中，没有性能提升，但更整洁的关系数据库管理系统是MS SQL。标记它以区别于MySql、Oracle等是一种很好的做法。感谢jean和Garethdn没有问题很高兴它帮助您现在可以接受答案：）我的客户决定他们现在希望看到十进制的比例-这可以通过CAST调用完成，还是我必须以不同的方式编码？
SELECT  Q.Query_Name
       ,Q.Attempts
       ,Q.Successes
       ,Q.Failures
       ,CAST(Q.[Successes] AS NVARCHAR(10)) + '/' + CAST(Q.[Attempts] AS NVARCHAR(10)) AS Proportion
FROM (
SELECT generate_query AS Query_Name, 
       sum(case when RecNum is NOT NULL then 1 else 0 end) AS Attempts, 
       sum(case when Query_test = 'Yes' then 1 else 0 end) AS Successes,
       sum(case when Query_test = 'No' then 1 else 0 end) AS Failures
       FROM tbl_TPF 
       GROUP BY generate_query 
     )Q
ORDER BY Q.Query_Name