How do I filter custom fields with value null in URL query

[Miraculous Ladybug]

Let's say I have a list of issues. But some of them have a custom field with value null in my json ("customfield_number":null), since it's optional. How can I filter issues with only non null custom field?

I tried

https://jira.company.com/rest/api/2/search?jql=project=key&maxResults=1000&customfield_number%21%3Dnull

 also 

https://jira.companyname.com/rest/api/latest/search?jql=cf%5Bnumber%5D%20is%20not%20EMPTY

But none of these affected the results, at all...

[Radek Dostál · Accepted solution]

The second url says "is not empty" but you are searching for null. Could it be you meant

 "customfield" IS EMPTY

instead?

Assuming that api/2/search jql param works the same way as typing it out to navigator (you can do the same with /issues/?jql= ..) then above should be working.

Also, it's part of the jql - not a separate parameter, so

?jql=project = <key> and cf[12345] is empty&maxResults=1000

Trying locally that seems to do the work.

[Miraculous Ladybug]

I need to filter out values with null, I'm not searching for null. I need all issues where customfield is not null

If I try to modify the URL like above I get error code 400

EDIT: Thank you so so so much! It finally works after a day of failure, the way you said that customfield_nr is part of the jql query clicked something in me!! So my query looks like this

```search?jql=project=key+and+cf[id]+is+not+empty``` with plus signs in between