SQL Server从主键在另一个表中不显示为外键的表中进行选择

我有三张桌子-

User                UserID PK

SecurityGroup       SecurityGroupID PK, SecurityGroupName

UserSecurityGroup   UserSecurityGroupID, UserID FK, SecurityGroupID FK

我试图选择用户不属于的安全组的名称

用户可以是多个组的成员

i、 我有三个安全组：管理员、版主、成员

我传递一个用户ID。所述用户被分配到管理员组和版主组，但不属于成员组。我正在尝试显示“成员”

以下是我迄今为止的尝试：

尝试1-

select tblSecurityGroup.SecurityGroupName
from tblSecurityGroup
    inner join tblUserSecurityGroup
        on tblSecurityGroup.SecurityGroupID = tblUserSecurityGroup.SecurityGroupID
    inner join tblUser
        on tblUserSecurityGroup.UserID = tblUser.UserID
where tblUser.UserID = 1
    and tblSecurityGroup.SecurityGroupID not in (tblUserSecurityGroup.SecurityGroupID);

select tblSecurityGroup.SecurityGroupName
from tblSecurityGroup
    inner join tblUserSecurityGroup
        on tblSecurityGroup.SecurityGroupID = tblUserSecurityGroup.SecurityGroupID
    inner join tblUser
        on tblUserSecurityGroup.UserID = tblUser.UserID
where tblUser.UserID = 1
    and not exists (select tblSecurityGroup.SecurityGroupID
                    from tblSecurityGroup
                    where tblUserSecurityGroup.SecurityGroupID = tblSecurityGroup.SecurityGroupID);

尝试2-

select tblSecurityGroup.SecurityGroupName
from tblSecurityGroup
    inner join tblUserSecurityGroup
        on tblSecurityGroup.SecurityGroupID = tblUserSecurityGroup.SecurityGroupID
    inner join tblUser
        on tblUserSecurityGroup.UserID = tblUser.UserID
where tblUser.UserID = 1
    and tblSecurityGroup.SecurityGroupID not in (tblUserSecurityGroup.SecurityGroupID);

select tblSecurityGroup.SecurityGroupName
from tblSecurityGroup
    inner join tblUserSecurityGroup
        on tblSecurityGroup.SecurityGroupID = tblUserSecurityGroup.SecurityGroupID
    inner join tblUser
        on tblUserSecurityGroup.UserID = tblUser.UserID
where tblUser.UserID = 1
    and not exists (select tblSecurityGroup.SecurityGroupID
                    from tblSecurityGroup
                    where tblUserSecurityGroup.SecurityGroupID = tblSecurityGroup.SecurityGroupID);

---

非常感谢您为nooby学生提供指导。

您的问题可以通过

not exists

查询来回答。这里有一种方法：

select sg.SecurityGroupName
from tblSecurityGroup sg
where not exists (select 1
                  from tblUserSecurityGroup usg 
                  where sg.SecurityGroupID = usg.SecurityGroupID and
                        usg.UserID = 1
                 );

---

请注意，不需要

tblUser

，因为

UserID

位于

tblUserSecurityGroup

中。这些尝试的结果是什么？完全运行我的查询不会返回任何结果。运行除最后一行之外的每次尝试都会返回用户所属的安全组。您使用的是MySQL还是SQL Server？不要给未涉及的产品贴标签…抱歉，标签已经修改。谢谢！工作是一种享受。