Hi @nmarceloromero,
I understand that the custom field “Sprint de début planifié” contains only the issue key and no other information.
You can create calculated measures to look up the issue with the same key as “Sprint de début planifié” and get its name or another property (creation date, assignee, status, etc). However, this calculation works only as a descriptive field when you select issues on report rows and can not be transformed into a dimension.
Consider creating a new calculated custom field that would check on the “Sprint de début planifié” summary during data import. The principle is to use REST API and request more data with getDocument() function.
Please see this Community post for ideas and examples of requestion additional data on linked issues: Import fields in eazyBI from Checklist for Jira app.
Best,
Zane / support@eazyBI.com