Filter query : Categories with fewer than 10 products not working

[TravelTechCode]

Hi DJ, First of all Thanks for the amazing content on odata filter.

the filter query Categories?$filter=Products/$count lt 10 does not work and throws an error . I am running it via postman

this is my whole query https://developer-challenge.cfapps.eu10.hana.ondemand.com/odata/v4/northbreeze/Categories?$filter=Products/$count lt 10

Is there any changes in the filters ?? { "error": { "code": "500", "message": "/An association can't be used as a value in an expression/" } }