sql - 根据其他表的结果从表中选择

Question

首先，这是我没有创建且无法更改的数据库设置（Access 2010）：

违规行为：

套餐：

当给定的 Role1 和 Role2 匹配记录时，我想选择 WorkPackageCodes。例如，如果 Role1 为 3，Role 2 为 8，我想要 ID 为 3 和 8 的 WorkPackageCodes。例如，如果 Role1 为 4，Role2 为 6，则不应选择任何内容。

我通过多个查询实现了这一点，但我想在一个查询中实现这一点（有/没有子查询）。所以我需要一些东西，我可以在其中查看 WorkPackageID 是否在另一个表的结果集中。我试过这个：

//3 and 6 will be replaced by parameters
SELECT Role1 AS role FROM tblSODViolations
UNION
SELECT Role2 FROM tblSODViolations
WHERE Role1 = 3 AND Role2 = 6

这给了我想要的结果，我尝试进行一个查询，如下所示：

SELECT WorkPackageCode
FROM tblWorkPackages
WHERE WorkPackageID IN (SELECT Role1 AS r FROM tblSODViolations
                        UNION ALL
                        SELECT Role2 FROM tblSODViolations
                        WHERE Role1 = 3 AND Role2 = 6);

但如果我运行它，我会收到以下消息：

子查询中不允许此操作。

那么我该如何实现呢？或者有没有办法在某种 SQL if 语句中选择 WorkPackageCode？提前致谢！

Answer 1

尝试将其作为联接：

SELECT WorkPackageCode
FROM tblWorkPackages wp join
     tblSODViolations v
     on wp.WorkPackageID in (v.Role1, wp.WorkPackageId = v.Role2) and
        v.Role1 = 3 and v.Role2 = 6;

这可能会产生重复。如果是这样，

SELECT distinct WorkPackageCode
FROM tblWorkPackages wp join
     tblSODViolations v
     on wp.WorkPackageID in (v.Role1, wp.WorkPackageId = v.Role2) and
        v.Role1 = 3 and v.Role2 = 6;

但是，我不清楚为什么这不起作用：

SELECT WorkPackageCode
FROM tblWorkPackages wp
WHERE wp.WorkPackageID in (3, 6);

你也可以这样写：

SELECT WorkPackageCode
FROM tblWorkPackages wp
WHERE wp.WorkPackageID in (3, 6) and
      exists (select 1 from tblSODViolations where Role1 = 3 and Role2 = 6)

此特定版本最接近您描述所需内容的方式。

Answer 2

将联合创建为内联表并使用它来限制结果。

SELECT WorkPackageCode
FROM tblWorkPackages WP
INNER JOIN 
(SELECT Role1 AS r FROM tblSODViolations
                        UNION ALL
                        SELECT Role2 FROM tblSODViolations
                        WHERE Role1 = 3 AND Role2 = 6) B 
on B.R = WP.WorkPackageID;

或者...

Select workpackageCode 
FROM tblWorkPackages WP
INNER JOIN tblSODViolations V on V.WorkPackageID=WP.Role1
OR V.workPackageID=WP.Role2
WHERE V.Role1=3 and V.Role2=6