Google big query count - sql

Question

I am trying to pull all the customers having less than 4 orders
in past 3 months in Google BigQuery.
SELECT a.user_id, b.refer_by, FROM water_db.tb_order a INNER JOIN
water_auth.tb_users b ON a.user_id = b.user_id WHERE ( SELECT
user_id FROM
water_db.tb_order GROUP BY
user_id HAVING
COUNT(DISTINCT(a.user_id <= 4))) AND status = 3 AND DATE(a.order_date) >=
'2017-02-15' AND DATE(a.order_date) <= '2017-05-15';------

Answer 1

I'm guessing that each time a record is added to the table it equates to an order but something like:
SELECT
a.userid, b.refer_by
FROM water_db.tb_order a
INNER JOIN water_auth.tb_users b ON a.user_id = b.user_id
WHERE
(COUNT(userid) < 4)
and
DATE_ADD(MONTH, -4, a.order_date)
The date function may differ as I'm not 100% sure what it is in Google Big Query

Answer 2

I think the best way to approach this is by selecting from the users table, so you don't need to deduplicate IDs, and just expressing the condition as part of your WHERE clause. This should help get you started:
#standardSQL
SELECT
user_id,
refer_by
FROM water_db.tb_users
WHERE (
SELECT COUNT(*)
FROM water_db.tb_order
WHERE tb_users.user_id = tb_order.user_id AND
status = 3 AND
DATE(order_date) BETWEEN '2017-02-15' AND '2017-05-15'
) <= 4;
In this query, the join is expressed as a correlated subquery involving the two tables. You can try it out using sample data with this query:
#standardSQL
WITH tb_users AS (
SELECT 1 AS user_id, 'foo#bar.com' AS refer_by UNION ALL
SELECT 2, 'a#b.com' UNION ALL
SELECT 3, 'baz#baz.com'
),
tb_order AS (
SELECT 1 AS user_id, TIMESTAMP '2017-04-12' AS order_date, 3 AS status UNION ALL
SELECT 2, TIMESTAMP '2017-05-03', 3 UNION ALL
SELECT 1, TIMESTAMP '2017-03-13', 3 UNION ALL
SELECT 1, TIMESTAMP '2017-02-28', 3 UNION ALL
SELECT 2, TIMESTAMP '2017-05-06', 3 UNION ALL
SELECT 1, TIMESTAMP '2017-05-01', 3 UNION ALL
SELECT 1, TIMESTAMP '2017-05-02', 3
)
SELECT
user_id,
refer_by
FROM tb_users
WHERE (
SELECT COUNT(*)
FROM tb_order
WHERE tb_users.user_id = tb_order.user_id AND
status = 3 AND
DATE(order_date) BETWEEN
'2017-02-15' AND '2017-05-15'
) <= 4;