I tried searching around but couldn't find anything that would help me out.

I'm trying to do this in SQL:

```
DECLARE @onlyMM INT

SET @onlyMM = 1

SELECT *
FROM cdn.magnag
WHERE CASE @onlyMM
        WHEN 1
            THEN man_zrdtyp NOT IN (
                    1616
                    ,2001
                    )
        ELSE - 1
        END

```

I have a problem with: 

```
where case @onlyMM when 1 then man_zrdtyp not in (1616,2001) else -1 end

```

how to properly make a `case` for the operator `not in`?