It would be useful if we could add a search clause that compared two fields, especially for date fields.

For example, we have two custom fields called "From Date" and "To Date" that represent the date range the document was considered effective (vs draft or obsolete). It would be great to search for records on which the "To Date" is less than the "From Date". We could set up a Metadata Validation rule using that search clause as well.

Another example is if we have a Date Reviewed and compare that to the Date Modified. We could find any records that have changed after their review date to review them again.

We could find containers whose destruction date is less than that of their contents, or vice versa.

Other use cases might be to verify that a field on the a document matches the same field on its container.