A script to reveal which accounts have access to your SQL Server via Windows Groups. If you use Windows Authentication and have Windows groups as log-ins this script can help by revealing members of Windows Groups, and their current permissions. This is particularly handy if you're not the network administrator, or don't have access to the Active Directory tools.

/* -----------------------------------------------------

SQL Server - Windows Group Membership Checker

A script to reveal which accounts have access to your SQL Server via Windows
Groups. If you use Windows Authentication and have Windows groups as log-ins
this script can help by revealing members of Windows Groups, and their current
permissions. This is particularly handy if you're not the network administrator,
or don't have access to the Active Directory tools.

----------------------------------------------------- */

declare @CurrentRow int;
declare @TotalRows int;

set @CurrentRow = 1;

declare @SqlGroupMembership table(
    ACCOUNT_NAME sysname,
    ACCOUNT_TYPE varchar(30),
    ACCOUNT_PRIVILEGE varchar(30),
    MAPPED_LOGIN_NAME sysname,
    PERMISSION_PATH sysname
);

declare @WindowsGroupsOnServer table
(
    UniqueRowID int identity(1, 1) primary key not null,
    Name sysname
);

insert into @WindowsGroupsOnServer(NAME)
    select NAME
    from master.sys.server_principals
    where TYPE = 'G';

select @TotalRows = max(UniqueRowID)
from @WindowsGroupsOnServer;

declare @WindowsGroupName sysname;

-- Loop Each Windows Group present on the server
while @CurrentRow <= @TotalRows
    begin
        select @WindowsGroupName = Name
        from @WindowsGroupsOnServer
        where UniqueRowID = @CurrentRow;

        begin try
            -- Insert found logins into table variable
            insert into @SqlGroupMembership(
                ACCOUNT_NAME,
                ACCOUNT_TYPE,
                ACCOUNT_PRIVILEGE,
                MAPPED_LOGIN_NAME,
                PERMISSION_PATH)
            exec xp_logininfo @WindowsGroupName, 'members';
        end try

        begin catch
            -- No action for if xp_logininfo fails
        end catch;

        select @CurrentRow = @CurrentRow + 1;
    end;

-- Display final results
select
    @@servername    as Servername,
    PERMISSION_PATH as WindowsGroup,
    Account_Name,
    Mapped_Login_Name,
    Account_Type,
    Account_Privilege
from @SqlGroupMembership
order by PERMISSION_PATH, ACCOUNT_NAME;