Rest Aggregate match query

Hi i’m using an aggregate query to $sum values in my data - that’s working fine - but I’d like to filter the data based on the value of a pointer column.

Everything I’ve tried ends in a server error

{too many different attempts to list}


no results:
match = {“whichComp”:{"__type":“Pointer”, “className”: “Competitions”, “objectId”:“BSEvDF9Qna”}}

In normal (non aggregate) queries I’ve had success with where parameters, but I just can’t get match to work.

As you’ve proabably guest I’m a total noob novice when it comes to programming - and am just using parse server as an AppGyuver back end.

Any help would be massively appreciated.