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mediumSQLrecursive CTEsSingle-choice MCQ

This recursive CTE walks a graph that can contain cycles. Which technique correctly prevents infinite recursion in portable SQL?

WITH RECURSIVE walk(id, path) AS ( SELECT id, ARRAY[id] FROM nodes WHERE id = 1 UNION ALL SELECT e.dst, w.path || e.dst FROM walk w JOIN edges e ON e.src = w.id WHERE /* ??? */ ) SELECT * FROM walk;