This module extends Views by allowing you to filter based on the absence of related content. It provides a way to create lists of items that do not have specific associated data, enabling more complex queries.
The Views Relationship Condition module allows site admins to configure filters or contextual filters on a view so that the filter is applied to a relationship, instead of the whole query.
This allows the creation of views which list items which do not have related items with certain properties. For example:
- Taxonomy terms which are not on published nodes.
- Nodes which do not have a taxonomy term which is a root term
- Items which do not have a report for the current year.
Limitations
Because this module alters the query for a view, it has a few limitations with what it can alter:
- The relationship option is only available on filters for single-valued base fields. It is not available on multi-valued base fields, bundle fields, or config fields. This is because these have their own field data table, which would need to be grouped in the query join, and the Views sql query plugin does not support this.
- The 'exclude' option on contextual filters is not supported.
- Multiple values on a contextual filter are not supported.
- Some value types may not work correctly if they have a custom filter or argument plugin which does specialised things to the query.