-- trap: a WHERE the NULL row of the order table passes keeps the outer join (the anti join of the stores without orders): the rows must be those of the outer join, from either plan (the scan answers it with the stores preserved, as fast as the normal plan: 0.6 ms each)
-- shape: trap
-- expect: any
-- key: -
-- scenario: yes
SELECT s.kind, count(*) AS tenants
FROM tenants s LEFT JOIN orders o ON o.tenant_id = s.id
WHERE o.id IS NULL
GROUP BY s.kind ORDER BY s.kind