XPathMissingInstanceException when counting a filtered Entity List

[aankrah]

I am trying to upload a form to Central with the calculation
count(instance('farmers')/root/item[farmer_community=${farmer_community}]) and it fails with the error shown below.
I thought creating the entity list (without the attributes) could help the situation but that didn't.

What I'm trying to do is to count the number of entities from a specified community and increment the value by 1 to be used as an "ID" for the new entity being created. Is there a better way to do this?

[Sadiq_Khoja]

Can you please share the XLSForm? This looks similar to this thread though:

How to get max value of a csv file

Hi all, Here my question : I'd like to increment by 1 the value of the "id" question of my formular. For the moment I'm tring to use entities and to get the max value of the "id" field. Here is the survey tab : [Capture1] Here is my entities tab : [Capture2] Here is my entities fields : [Capture3] I attach my xls form gestionBouquetinsMarques.xls (70.5 KB) Thanks a lot for any ideas !

[LN]

I'm wondering whether in this specific case the issue could be that you didn't explicitly attach the farmers Entity List. Currently you need to explicitly attach even the Entity List that a form creates or updates Entities in. You can do this with a csv-external question type that has name farmers and learn more in the docs.

We've seen a number of users get tripped up by this so we are thinking about the best way to improve it.