CREATE TABLE event (
  user_id BIGINT,
  event_id BIGINT,
  time BIGINT NOT NULL,
  data JSON NOT NULL,
  PRIMARY KEY (user_id, event_id)
)

SELECT
user_id,
view_homepage,
view_homepage_time,
enter_credit_card,
enter_credit_card_time
FROM (
-- Get the first time each user viewed the homepage.
SELECT
user_id,
1 AS view_homepage,
min(time) AS view_homepage_time
FROM event
WHERE
data->>'type' = 'view_homepage'
GROUP BY user_id
) e1 LEFT JOIN LATERAL (
-- For each row, get the first time the user_id did the enter_credit_card
-- event, if one exists within two weeks of view_homepage_time.
SELECT
1 AS enter_credit_card,
time AS enter_credit_card_time
FROM event
WHERE
user_id = e1.user_id AND
data->>'type' = 'enter_credit_card' AND
time BETWEEN view_homepage_time AND (view_homepage_time + 1000*60*60*24*14)
ORDER BY time
LIMIT 1
) e2 ON true

SELECT
  user_id,
  1 AS view_homepage,
  min(time) AS view_homepage_time
FROM event
WHERE
  data->>'type' = 'view_homepage'
GROUP BY user_id

SELECT
  1 AS enter_credit_card,
  time AS enter_credit_card_time
FROM event
WHERE
  user_id = e1.user_id AND
  data->>'type' = 'enter_credit_card' AND
  time BETWEEN view_homepage_time AND (view_homepage_time + 1000*60*60*24*14)
ORDER BY time
LIMIT 1

user_id | view_homepage | view_homepage_time | enter_credit_card | enter_credit_card_time
---------+---------------+--------------------+-------------------+------------------------
567 | 1 | 5234567890 | 1 | 5839367890
234 | 1 | 2234567890 | |
345 | 1 | 3234567890 | |
456 | 1 | 4234567890 | |
678 | 1 | 6234567890 | |
123 | 1 | 1234567890 | |
... 

SELECT
  sum(view_homepage) AS viewed_homepage,
  sum(enter_credit_card) AS entered_credit_card
FROM (
  -- Get the first time each user viewed the homepage.
  SELECT
  user_id,
  1 AS view_homepage,
  min(time) AS view_homepage_time
  FROM event
  WHERE
  data->>'type' = 'view_homepage'
  GROUP BY user_id
) e1 LEFT JOIN LATERAL (
  -- For each (user_id, view_homepage_time) tuple, get the first time that
  -- user did the enter_credit_card event, if one exists within two weeks.
  SELECT
  1 AS enter_credit_card,
  time AS enter_credit_card_time
  FROM event
  WHERE
  user_id = e1.user_id AND
  data->>'type' = 'enter_credit_card' AND
  time BETWEEN view_homepage_time AND (view_homepage_time + 1000*60*60*24*14)
  ORDER BY time
  LIMIT 1
) e2 ON true

 viewed_homepage | entered_credit_card
-----------------+---------------------
827 | 10

SELECT
  sum(view_homepage) AS viewed_homepage,
  sum(use_demo) AS use_demo,
  sum(enter_credit_card) AS entered_credit_card
FROM (
  -- Get the first time each user viewed the homepage.
  SELECT
  user_id,
  1 AS view_homepage,
  min(time) AS view_homepage_time
  FROM event
  WHERE
  data->>'type' = 'view_homepage'
  GROUP BY user_id
) e1 LEFT JOIN LATERAL (
  -- For each row, get the first time the user_id did the use_demo
  -- event, if one exists within one week of view_homepage_time.
  SELECT
  user_id,
  1 AS use_demo,
  time AS use_demo_time
  FROM event
  WHERE
  user_id = e1.user_id AND
  data->>'type' = 'use_demo' AND
  time BETWEEN view_homepage_time AND (view_homepage_time + 1000*60*60*24*7)
  ORDER BY time
  LIMIT 1
) e2 ON true LEFT JOIN LATERAL (
  -- For each row, get the first time the user_id did the enter_credit_card
  -- event, if one exists within one week of use_demo_time.
  SELECT
  1 AS enter_credit_card,
  time AS enter_credit_card_time
  FROM event
  WHERE
  user_id = e2.user_id AND
  data->>'type' = 'enter_credit_card' AND
  time BETWEEN use_demo_time AND (use_demo_time + 1000*60*60*24*7)
  ORDER BY time
  LIMIT 1
) e3 ON true

 viewed_homepage | use_demo | entered_credit_card
-----------------+----------+---------------------
827 | 220 | 86