Buyers structure by registration date query optimisation - mysql

Question

I would like to show buyers structure by their registration date e.g.:
H12016 10.000 buyers
from which
2.000 registered in H12014
4.000 registered in H22014
etc.
I have two queries for that:
Number 1 (buyers from H12016 (about 50k records)):
SELECT DISTINCT
r.idUsera as id_usera
FROM
rezerwacje r
WHERE
r.dataZalozenia between '2016-01-01' and '2016-07-01'
and r.`status` = 'zabookowana'
ORDER BY
id_usera
Number 2 (users_ids and their registration (insert) date (about 3,8M users)):
SELECT
m.user_id,
date(m.action_date) as data_insert
FROM
mwids m
WHERE
m.`type` = 'insert'
Both queries separately run fine, but when I try to combine them like so:
SELECT DISTINCT
r.idUsera as id_usera,
t1.data_insert
FROM
rezerwacje r
LEFT JOIN
(
SELECT
m.user_id,
date(m.action_date) as data_insert
FROM
mwids m
WHERE
m.`type` = 'insert'
) t1 ON t1.user_id = r.idUsera
WHERE
r.dataZalozenia between '2016-01-01' and '2016-07-01'
and r.`status` = 'zabookowana'
ORDER BY
id_usera
this query runs "indefinetely" and I have to kill it after some time.
I do not belive it should run that long. If the query Number 2 was smaller i.e. about 1M users I could combine results in Excel in matter of seconds. So why is it not possible inside the database? What am I doing wrong?

Answer 1

SELECT DISTINCT
r.idUsera as id_usera,
t1.data_insert
FROM
rezerwacje r
INNER JOIN
(
SELECT
m.user_id,
date(m.action_date) as data_insert
FROM
mwids m
WHERE
m.`type` = 'insert'
) t1 ON t1.user_id = r.idUsera
WHERE
r.dataZalozenia between '2016-01-01' and '2016-07-01'
and r.`status` = 'zabookowana'
ORDER BY
id_usera
Try with INNER JOIN.

Answer 2

Query 1 needs
INDEX(status, dataZalozenia, id_usera)
Query 3: Rewrite thus:
If there is only one row in mwids for 'insert' per user:
SELECT r.idUsera as id_usera, DATE(m.action_date) AS data_insert
FROM rezerwacje r
LEFT JOIN mwids m ON m.user_id = r.idUsera
AND m.`type` = 'insert'
WHERE r.dataZalozenia >= '2016-01-01'
AND r.dataZalozenia < '2016-01-01' + 12 MONTH
and r.`status` = 'zabookowana'
ORDER BY r.idUsera
with
INDEX(status, dataZalozenia, isUsera) -- on r
INDEX(type, user_id, action_date) -- on m
If there can be multiple rows, do this:
SELECT r.idUsera as id_usera,
( SELECT DATE(m.action_date)
FROM mwids m
WHERE m.user_id = r.idUsera
AND m.`type` = 'insert'
LIMIT 1
) AS data_insert
FROM rezerwacje r
LEFT JOIN mwids m ON m.user_id = r.idUsera
AND m.`type` = 'insert'
WHERE r.dataZalozenia >= '2016-01-01'
AND r.dataZalozenia < '2016-01-01' + 12 MONTH
and r.`status` = 'zabookowana'
ORDER BY r.idUsera
But you will be getting a random action_date. So maybe you want MIN() or MAX()?