Get Issues with non blank customfields ?

[Namrata Joshi]

I have a custom field on Issue, Its blank(not null) for few Issues and contains some value for few.

tried mostly all jql option similar to cf[100010] IS NOT EMPTY or cf[100010] !~""

Please suggest appropriate jql

Querying : cf[10..00] !~ ''  returns 

{
"errorMessages": [
"The field 'cf[10..00]' does not support searching for an empty string."
],
"errors": {}
}

[Nic Brough -Adaptavist-]

What type of field is it?  Most fields will not actually take a blank string as valid content, internally, they'll go "oh, nothing, ok, I'll store it as empty"

[Namrata Joshi]

I have installed metadata add-on for project level custom field; and set Key=project.ID and Value = xyz and created a new Custom field of type "JIRA Metadata - View project metadata field" and set default value as project.ID. It's properly showing that field in my issue. For only 1 Project metadata(key/value) is set and for other projects its not set. from JIRA API, for other Issues other than this project its displaying customefield as ""

[Nic Brough -Adaptavist-]

I'm not sure how the metadata stuff stores its data, or how the searcher for it works.