使用 IN 语句的 Where 子句中的 Case 语句

不确定这是否可行，但我想根据某些条件在 IN 语句中指定一个选择查询。这是我的 SQL 查询：

SET @DepartmentId = (SELECT TOP 1 DepartmentId FROM Organisations WHERE OrganisationId = @OrgId)

CREATE TABLE #JustificationDetails
(
    JustificationId INT,
    Code VARCHAR(5),
    AccCategory CHAR(2),
    Description VARCHAR(200),
    ActualTotals DECIMAL(18, 2),
    CurrentTotals DECIMAL(18, 2),
    FutureTotals DECIMAL(18, 2),
    IncreaseDecreaseTotals DECIMAL(18, 2),
    IncreaseDecreasePerc INT,
    Justification VARCHAR(MAX)
)

INSERT INTO #JustificationDetails
    SELECT 
        ISNULL(J.pkiJustificationId, 0), 
        RIGHT(A.AccountNumber, 5) AS AccVote, 
        LEFT(RIGHT(A.AccountNumber, 5), 2) AS AccCategory, 
        A.Description, 
        0, 0, 0, 0, 0,
        ISNULL(J.JustificationReason, '''')
    FROM 
        Accounts A 
    INNER JOIN 
        Notes_Line_Entries NLE ON A.AccountId = NLE.fkiAccountId
    INNER JOIN 
        MasterBudgets MB ON NLE.budgetId = MB.BudgetId
    INNER JOIN 
        Organisations O ON MB.OrganisationId = O.OrganisationId
    LEFT JOIN 
        Justifications J ON O.OrganisationId = J.fkiOrganisationId
    WHERE 
        fkiNotesColumnId = 3 
        AND O.OrganisationId IN (CASE
                                    WHEN @DepartmentId = 2 
                                       THEN (SELECT OrganisationId FROM Organisations
                                             WHERE ParentOrganisationId IN (SELECT OrganisationId 
                                                                                            FROM Organisations 
            WHERE ParentOrganisationId IN (SELECT OrganisationId 
                                           FROM Organisations 
                                           WHERE ParentOrganisationId = @OrgId)))
                                    WHEN @DepartmentId = 4 
                                       THEN (SELECT OrganisationId FROM Organisations
                                             WHERE ParentOrganisationId IN (SELECT OrganisationId 
            FROM Organisations 
            WHERE ParentOrganisationId IN (SELECT OrganisationId 
                                           FROM Organisations 
                                           WHERE ParentOrganisationId = @OrgId)))
                                    WHEN @DepartmentId = 3 
                                       THEN (SELECT OrganisationId 
                                             FROM Organisations 
                                             WHERE ParentOrganisationId IN (SELECT OrganisationId 
           FROM Organisations 
           WHERE OrganisationId = @OrgId))
                                    WHEN @DepartmentId = 5 
                                       THEN (SELECT OrganisationId
                                             FROM Organisations 
                                             WHERE ParentOrganisationId IN (SELECT OrganisationId 
           FROM Organisations 
           WHERE OrganisationId = @OrgId))
                                 END)
GROUP BY 
    J.pkiJustificationId, A.Category, A.Description, 
    RIGHT(A.AccountNumber, 5), J.JustificationReason
ORDER BY 
    A.Category, RIGHT(A.AccountNumber, 5)

我收到以下错误：

子查询返回了 1 个以上的值。当子查询跟随 =、!=、<、<=、>、>= 或当子查询用作表达式时，这是不允许的。

如果我在 IN() 语句中只运行一个选择查询，那么它就可以工作，所以我只是假设这是不可能的？

谢谢你的帮助。