Find problems with set is empty

State the rule as a violation query: every row it returns is a problem, and the failure message hands over the culprits. Every fact is on the documentation page it links; the same page as markdown is at the URL with index.md appended, which is the form to read when your fetch tool summarizes HTML.

The pattern

Select the columns that identify the row and show the problem, the key and the offending value, not *; that is what will be read in the message. The examples, what comes back when it fails, the three properties that size the message, and the cost trick (TOP 1 or LIMIT 1 when the count is not needed): https://docs.justcat.it/how-to-guides/test-patterns/find-problems-with-set-is-empty/

The expectation's page, with Maximum errors logged, Log number of errors and the COUNT(*) trap: https://docs.justcat.it/reference/tests/expectations/set-is-empty/

A rule that sounds like a missing expectation