How to get active orders for past year - mysql

Question

I have a table which has start and end date. Based on that table, I have to get the active orders for the past 12 months.
In end date NULL means it is active order until now.
Table Basic idea
Expected Output
Based on the past experience I'm able to write the query like this for the current year January but i need it for all the months as shown in the above picture
select
mnth.num, count(*)
from (
select 1 AS num union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all
select 7 union all select 8 union all select 9 union all select 10 union all select 11 union all select 12
) mnth
left join (
select
o.id
, case
when o.start_date < date_format(current_date(), '%Y-01-01') then 1
else month(o.start_date)
end AS start_month
, case
when o.end_date < date_format(current_date(), '%Y-01-01') then 0
when o.end_date >= date_format(current_date(), '%Y-01-01') then month(o.end_date)
else month(current_date())
end AS end_month
from order o
) active_work_orders on mnth.num between active_work_orders.start_month and active_work_orders.end_month
where mnth.num <= month(current_date())
group by
mnth.num
;
Based on the output I have to generate a graph. Kindly help on this
Fiddle link click here

Answer 1

Maybe something like this
select mthnum,
count(*)
from
(
select mthnum, o.*,year(start_date)* 12 + month(start_date),year(end_date) * 12 + month(end_date)
from
(
#select 2016*12 + 11 AS mthnum union all select 2016*12 + 12 union all select 2017*12 + 1 union all select 2017*12 + 2
select 2017*100 + 2 as mthnum
union all select 2017*100 + 3 union all select 2017*100 + 4 union all select 2017*100 + 5 union all select 2017*100 + 6
union all select 2017*100 + 7 union all select 2017*100 + 8 union all select 2017*100 + 9 union all select 2017*100 + 10
union all select 2017*100 + 11 union all select 2017*100 + 12 union all select 2018*100 + 1
) mth
cross join
(select * from order_test_new #where order_num = 1288
) o
) s where (s.mthnum >= year(s.start_date)*100 + month(start_date)) and
(end_date is null or s.mthnum <= year(end_date) * 100 + month(s.end_date))
group by mthnum
result
+--------+----------+
| mthnum | count(*) |
+--------+----------+
| 201702 | 9 |
| 201703 | 9 |
| 201704 | 9 |
| 201705 | 8 |
| 201706 | 8 |
| 201707 | 8 |
| 201708 | 8 |
| 201709 | 7 |
| 201710 | 7 |
| 201711 | 6 |
| 201712 | 6 |
| 201801 | 6 |
+--------+----------+
12 rows in set (0.00 sec)
This considers that an order with and end_date is active in the end_date month.

Answer 2

You can take the help of extract function to extract year and month and do a group by based on that.
Then, for displaying, you can use date_format function.
So, here it goes:
SELECT
DATE_FORMAT(start_date, '%b-%y') AS `Month`, COUNT(*) AS `Active`
FROM
orders
WHERE
end_date IS NULL
GROUP BY EXTRACT(YEAR_MONTH FROM start_date)
For getting result from last 12 months only, you can use the following:
SELECT
`month_list`.`month`, IFNULL(`active_orders`.`active_count`, 0) AS `active_count`
FROM
(SELECT
*
FROM
(SELECT DATE_FORMAT(NOW(), '%b-%y') AS `month`
UNION
SELECT DATE_FORMAT(NOW() - INTERVAL 1 MONTH, '%b-%y')
UNION
SELECT DATE_FORMAT(NOW() - INTERVAL 2 MONTH, '%b-%y')
UNION
SELECT DATE_FORMAT(NOW() - INTERVAL 3 MONTH, '%b-%y')
UNION
SELECT DATE_FORMAT(NOW() - INTERVAL 4 MONTH, '%b-%y')
UNION
SELECT DATE_FORMAT(NOW() - INTERVAL 5 MONTH, '%b-%y')
UNION
SELECT DATE_FORMAT(NOW() - INTERVAL 6 MONTH, '%b-%y')
UNION
SELECT DATE_FORMAT(NOW() - INTERVAL 7 MONTH, '%b-%y')
UNION
SELECT DATE_FORMAT(NOW() - INTERVAL 8 MONTH, '%b-%y')
UNION
SELECT DATE_FORMAT(NOW() - INTERVAL 9 MONTH, '%b-%y')
UNION
SELECT DATE_FORMAT(NOW() - INTERVAL 10 MONTH, '%b-%y')
UNION
SELECT DATE_FORMAT(NOW() - INTERVAL 11 MONTH, '%b-%y'))
AS `months`) as `month_list`
LEFT JOIN
(SELECT
DATE_FORMAT(start_date, '%b-%y') AS `month`, COUNT(*) AS `active_count`
FROM
`order`
WHERE
end_date IS NULL
GROUP BY EXTRACT(YEAR_MONTH FROM start_date)) as `active_orders` on `month_list`.`month` = `active_orders`.`month`;