How to filter CloudWatch Log Insights with ispresent() function

After a while, I figured out how to do that, in a hackish way.

fields @timestamp, status, ispresent(status) as exist
| filter exist != 0

Not the best way (and it goes against their documentation), but works.

The accepted answer doesn't work for me, but you can now negate ispresent():

fields @timestamp, status
| filter !ispresent(status)