CTE with multi rows + set default value

[xluffy]

WITH keke AS (
  SELECT '{"a":1,"b":2}'::jsonb AS attribute UNION ALL
  SELECT '{"a":1,"c":2}'::jsonb AS attribute UNION ALL
  SELECT '{"b":1,"c":2}'::jsonb AS attribute
)

--SELECT attribute FROM keke;
SELECT CASE 
	WHEN attribute->>'c' IS NOT NULL THEN attribute->>'c'
	WHEN attribute->>'c' IS NULL THEN 'default'
	END AS c FROM keke;