gistfile1.txt

SELECT
  SUM(funnel_events(
       ARRAY_AGG(funnel_step ORDER BY time ASC, funnel_step DESC), 
       2)) AS funnel_results
FROM ((SELECT *
        FROM (SELECT user_id,
                     time,
                     0 AS funnel_step
              FROM "events"
              WHERE type = 'click'
                AND text = 'Login'
                AND time BETWEEN 1476428400000 AND 1477033200000) events_1)
      UNION ALL
      (SELECT *
       FROM (SELECT user_id,
                    time,
                    1 AS funnel_step
             FROM "events"
             WHERE  type = 'click'
               AND text = 'Purchase'
               AND time BETWEEN 1476428400000 AND 1477033200000) events_2)
      ) events_query
GROUP BY user_id;

shoudn't the line 11 (AND text = 'Login') be AND text = 'SignUp', as the example is demonstrating

customer wants to know what percentage of the users who have signed up in a given week later made a purchase that same week [1]

How come Login is same as singed up ?