Support for Drupal 7 is ending on 5 January 2025—it’s time to migrate to Drupal 10! Learn about the many benefits of Drupal 10 and find migration tools in our resource center.
The following is designed for Projects and Tasks, but would probably work for any Entity Relationship with optional children of a parent.
To create a view that lists all parent nodes (in this case Project content type) whether they have children (in this case Tasks) or not use the following methodology.
The output will be all Projects with Tasks listed below them if they have Tasks.
Create a View for Projects. The Format chosen was Table, but other options would probably work.