Prior to SQL Server 2008 R2, members of the local Administrators group were automatically granted sysadmin privileges. This changed for security reasons, requiring explicit assignment of server roles. Microsoft's current recommendation is to create dedicated Windows groups for database administrators and assign them the sysadmin role.

Before proceeding, ensure:

• You have sysadmin privileges on the SQL Server instance
• The Windows group exists in Active Directory or local machine
• SQL Server is configured for Windows Authentication mode

Using SQL Server Management Studio (SSMS):

1. Connect to your SQL Server instance
2. Expand Security > Logins
3. Right-click and select "New Login"
4. Click "Search" and locate your Windows group
5. Select "Server Roles" in left pane
6. Check the "sysadmin" checkbox
7. Click OK to save

T-SQL Implementation:

USE [master]
GO
CREATE LOGIN [DOMAIN\YourDbaGroup] FROM WINDOWS
GO
EXEC sp_addsrvrolemember 'DOMAIN\YourDbaGroup', 'sysadmin'
GO

To verify the assignment:

SELECT name, type_desc, is_disabled 
FROM sys.server_principals 
WHERE IS_SRVROLEMEMBER('sysadmin', name) = 1;

Common issues include:

• Group not found (verify domain spelling)
• Insufficient permissions (must have sysadmin rights)
• SQL Server not in Windows Authentication mode

When implementing this approach:

1. Create dedicated groups for specific roles (e.g., SQL_Admins, SQL_Developers)
2. Follow principle of least privilege
3. Regularly audit group memberships
4. Document all role assignments

For environments where group assignment isn't possible:

-- Create a SQL login with sysadmin privileges
CREATE LOGIN DBA_User WITH PASSWORD = 'ComplexP@ssw0rd!'
EXEC sp_addsrvrolemember 'DBA_User', 'sysadmin'

Remember that SQL logins should use strong passwords and preferably be combined with MFA solutions.

When upgrading from earlier versions:

-- Check for BUILTIN\Administrators membership
SELECT name 
FROM sys.server_principals 
WHERE name = 'BUILTIN\Administrators' 
AND IS_SRVROLEMEMBER('sysadmin', name) = 1;

Plan to transition from the legacy approach to the recommended group-based model.

Prior to SQL Server 2008 R2, members of the local BUILTIN\Administrators group were automatically granted sysadmin privileges. This changed for security reasons, requiring administrators to explicitly grant these permissions to specific Windows groups.

Here's how to properly grant a Windows group sysadmin privileges:

USE [master]
GO
CREATE LOGIN [DOMAIN\SQLAdmins] FROM WINDOWS WITH DEFAULT_DATABASE=[master]
GO
ALTER SERVER ROLE [sysadmin] ADD MEMBER [DOMAIN\SQLAdmins]
GO

1. Open SQL Server Management Studio
2. Connect to your SQL Server instance
3. Navigate to Security > Server Roles
4. Right-click "sysadmin" and select Properties
5. Click "Add" and search for your Windows group
6. Select the group and click OK twice to save changes

If you encounter errors when adding the group:

• Ensure you have sysadmin privileges to make this change
• Verify the group exists in Active Directory
• Check that the SQL Server service account has permissions to query AD
• Confirm the group name follows the correct format: DOMAIN\GroupName

When implementing this solution:

• Create a dedicated AD group for SQL Server administrators
• Document all members of this privileged group
• Consider implementing Just-In-Time access controls
• Regularly audit membership of this group

For environments with multiple servers, you can automate the process:

$servers = @("SQLServer1", "SQLServer2", "SQLServer3")
$group = "DOMAIN\SQLAdmins"

foreach ($server in $servers) {
    $sql = @"
USE [master]
GO
IF NOT EXISTS (SELECT * FROM sys.server_principals WHERE name = '$group')
BEGIN
    CREATE LOGIN [$group] FROM WINDOWS WITH DEFAULT_DATABASE=[master]
END
GO
ALTER SERVER ROLE [sysadmin] ADD MEMBER [$group]
GO
"@
    Invoke-Sqlcmd -Query $sql -ServerInstance $server
}