How to group mysql results in weeks - mysql

Question

I have a table like this:
I need to sum how many messages were delivered per msisdn in last 8 weeks(but for each week) from date entered. Here is what I came up with:
SELECT count(*) as ukupan_broj, SUM(IF (sent_messages.delivered = 1,1,0 )) as broj_dostavljenih,
count(*) - SUM(IF (sent_messages.delivered = 1,1,0 )) as non_billed,
SUM(IF (sent_messages.delivered = 1,1,0 )) / count(*) as ratio,
`sent_messages`.`msisdn`,
MONTH(`sent_messages`.`datetime`) AS MONTH, WEEK(`sent_messages`.`datetime`) AS WEEK,
DATE_FORMAT(`sent_messages`.`datetime`, '%Y-%m-%d') AS DATE
FROM `sent_messages`
INNER JOIN `received_messages` on `received_messages`.`uniqueid`=`sent_messages`.`originalID`
and `received_messages`.`msisdn`=`sent_messages`.`msisdn`
WHERE `sent_messages`.`datetime` >= '2016-12-12'
AND `sent_messages`.`originalID` = `received_messages`.`uniqueid`
AND `sent_messages`.`datetime` <= '2017-12-30'
AND `sent_messages`.`datetime` >= `received_messages`.`datetime`
AND `sent_messages`.`datetime` <= ( `received_messages`.`datetime` + INTERVAL 2 HOUR )
AND `sent_messages`.`type` = 'PAID'
GROUP BY WEEK
ORDER BY DATE ASC
And because I'm grouping it by WEEK, my result is showing sum of all delivered, undelivered etc. but not per msisdn. Here is how result looks like:
And when I add msisdn in GROUP BY clause I don't get the result the way I need it.
And I need it like this:
Please help me to write optimized query to fetch these results for each msisdn per last 8 weeks, because I'm stuck.

Answer 1

WEEK(...) has a problem near the first of the year. Instead, you could use TO_DAYS:
WHERE datetime > CURDATE() - INTERVAL 8 WEEK -- for the last 8 weeks
GROUP BY MOD(TO_DAYS(datetime), 7) -- group by week
That is quite simple, but there is a bug in it. It only works if today is the last day of a "week". And if date%7 lands on the desired day of week.
WHERE datetime > CURDATE() - INTERVAL 9 WEEK -- for the last 8 weeks
GROUP BY MOD(TO_DAYS(datetime) - 3, 7) -- group by week
Is the first cut at fixing the bugs -- 9-week interval will include the current partial week and the partial week 8 weeks ago. The "- 3" (or whatever number works) will align your "week" to start on Monday or Sunday or whatever.
SUM(IF (sent_messages.delivered = 1,1,0 )) can be shortened to SUM(delivered = 1) or even SUM(delivered) if that column only has 0 or 1 values.