MySQL - Update table with row number per group - mysql

Question

Sample Data
id | order_id | instalment_num | date_due
---------------------------------------------------------
1 | 10000 | 1 | 2010-07-09 00:00:00
2 | 10000 | 1 | 2010-09-06 11:39:56
3 | 10001 | 1 | 2014-04-25 15:46:52
4 | 10002 | 1 | 2010-01-11 00:00:00
5 | 10003 | 1 | 2010-01-04 00:00:00
6 | 10003 | 1 | 2016-05-31 00:00:00
7 | 10003 | 1 | 2010-01-08 00:00:00
8 | 10003 | 1 | 2010-01-06 09:06:26
9 | 10004 | 1 | 2010-01-11 11:25:07
10 | 10004 | 1 | 2010-01-12 07:06:42
Desired Result
id | order_id | instalment_num | date_due
---------------------------------------------------------
1 | 10000 | 1 | 2010-07-09 00:00:00
2 | 10000 | 2 | 2010-09-06 11:39:56
3 | 10001 | 1 | 2014-04-25 15:46:52
4 | 10002 | 1 | 2010-01-11 00:00:00
5 | 10003 | 1 | 2010-01-04 00:00:00
8 | 10003 | 2 | 2010-01-06 09:06:26
7 | 10003 | 3 | 2010-01-08 00:00:00
6 | 10003 | 4 | 2016-05-31 00:00:00
9 | 10004 | 1 | 2010-01-11 11:25:07
10 | 10004 | 2 | 2010-01-12 07:06:42
As you can see, I have an instalment_num column which should show the number/index of each row belonging to the order_id, determined by the date_due ASC, id ASC order.
How can I update the instalment_num column like this?
Additional Notes
The date_due column is not unique, and there may be many ids or order_ids with the exact same timestamp.
If the timestamp is the same for two rows belonging to the same order_id, it should order them by id as a fallback.
I require a query which will update this column.

Answer 1

This is how I would do it:
SELECT a.id,
a.order_id,
COUNT(b.id)+1 AS instalment_num,
a.date_due
FROM sample_data a
LEFT JOIN sample_data b ON a.order_id=b.order_id AND (a.date_due>b.date_due OR (a.date_due=b.date_due AND a.id>b.id))
GROUP BY a.id, a.order_id, a.date_due
ORDER BY a.order_id, a.date_due, a.id
UPDATE version attempt:
UPDATE sample_data
LEFT JOIN (SELECT a.id,
COUNT(b.id)+1 AS instalment_num
FROM sample_data a
JOIN sample_data b ON a.order_id=b.order_id AND (a.date_due>b.date_due OR (a.date_due=b.date_due AND a.id>b.id))
GROUP BY a.id) c ON c.id=sample_data.id
SET sample_data.instalment_num=c.instalment_num

Answer 2

For the numbering to begin with 1:
UPDATE sample_data
LEFT JOIN (SELECT a.id,
COUNT(b.id) AS instalment_num
FROM sample_data a
JOIN sample_data b ON a.order_id = b.order_id AND (a.date_due > b.date_due OR (a.date_due=b.date_due AND a.id + 1 > b.id))
GROUP BY a.id) c ON c.id = sample_data.id
SET sample_data.instalment_num = c.instalment_num

Answer 3

You are trying to achieve what ROW_NUMBER with a partition would do using something like SQL Server or Oracle. You can simulate this with an approriate query:
SELECT t.id, t.order_id,
(
SELECT 1 + COUNT(*)
FROM sampleData
WHERE (date_due < t.date_due OR (date_due = t.date_due AND id < t.id)) AND
order_id = t.order_id
) AS instalment_num,
t.date_due
FROM sampleData t
ORDER BY t.order_id, t.date_due
This query will order the instalment_num by due_date in ascending order. And in the case of a tie in due_date, it will order by the id in ascending order.
Follow the link below for a demo:
SQLFiddle

Answer 4

select
sub.order_id, sub.date_due,
#group_rn:= case
when #group_order_id=sub.order_id then #group_rn:=#group_rn:+1
else 1
end as instalment_num,
#group_order_id:=sub.order_id
FROM (select #group_rn:=0, group_order_id=0) init,
(select *
from the_table
order by order_id, date_due) sub