I'm trying to do a basic calculation in MS Access SQL.

I have a table called `Weekly`, with weekly stats for each user, includes the following columns: `User`, `Fail`, `Pass`, `Approve` and `Reject` (and some unimportant id and date values).

When I perform the following query:

```
SELECT User, Switch(Approve>0,Pass/Approve, Approve = 0, Null) AS passed_approved_ratio, Switch(Reject>0,Fail/Reject, Reject= 0, Null) AS fail_reject_ratio
FROM Weekly

```

I get an `#ERROR` value in several resulting rows.

I've tried it with and without the second condition+value in the `Switch` funciton (`Switch(Approve>0, Pass/Approve)`, 

Fail, Pass, Approve and Reject all have a non-null numerical value in the Weekly table, so why don't they resolve to a Null value when Approve or Reject are 0?