Tabelas sem chave primária

SELECT CONCAT(t.table_schema, '.', t.table_name) AS table_name,
       t.table_rows AS estimated_rows,
       t.engine
FROM information_schema.tables t
LEFT JOIN information_schema.table_constraints c
       ON c.table_schema = t.table_schema
      AND c.table_name = t.table_name
      AND c.constraint_type = 'PRIMARY KEY'
WHERE t.table_schema NOT IN ('mysql', 'information_schema', 'performance_schema', 'sys')
  AND t.table_type = 'BASE TABLE'
  AND c.constraint_name IS NULL
ORDER BY t.table_rows DESC