SQL Select Query for 365 Days - sql

Question

I am trying to create an SQL query to select percentage utilization for my team members.
I am looking for a to daily basis select query to show the utilization when it is greater than 0 and to show '0' when it is null. In order to be able to plot those figures later on as a line chart.
I have written 365 of the following select query and I have combined them together using "UNION ALL" method. It is working now, but it is extremely slow!.
If you have a better idea to produce the daily outputs for the 365 days, that will be great.
Many thanks in advance.
Kind regards
Mohamed
Code:
.........................
SELECT ifnull((
SELECT SUM(CAST(pc_loading.value AS INT))
FROM ticket
JOIN ticket_custom start_date ON (ticket.id = start_date.ticket AND start_date.name = 'planned_start_date')
JOIN ticket_custom finish_date ON (ticket.id = finish_date.ticket AND finish_date.name = 'planned_finish_date')
JOIN ticket_custom pc_loading ON (ticket.id = pc_loading.ticket AND pc_loading.name = 'percentage_loading')
WHERE UPPER(ticket.owner)='#########'
AND ticket.type = 'Internal Resource'
AND DATE(substr(start_date.value, 7, 4) || '-' || substr(start_date.value, 4, 2) || '-' || substr(start_date.value, 1, 2)) <= DATE('2020-01-01')
AND DATE(substr(finish_date.value, 7, 4) || '-' || substr(finish_date.value, 4, 2) || '-' || substr(finish_date.value, 1, 2)) >= DATE('2020-01-01')
AND status NOT IN ("closed", "suspended")) , 0) UNION ALL
SELECT ifnull((
SELECT SUM(CAST(pc_loading.value AS INT))
FROM ticket
JOIN ticket_custom start_date ON (ticket.id = start_date.ticket AND start_date.name = 'planned_start_date')
JOIN ticket_custom finish_date ON (ticket.id = finish_date.ticket AND finish_date.name = 'planned_finish_date')
JOIN ticket_custom pc_loading ON (ticket.id = pc_loading.ticket AND pc_loading.name = 'percentage_loading')
WHERE UPPER(ticket.owner)='#########'
AND ticket.type = 'Internal Resource'
AND DATE(substr(start_date.value, 7, 4) || '-' || substr(start_date.value, 4, 2) || '-' || substr(start_date.value, 1, 2)) <= DATE('2020-01-02')
AND DATE(substr(finish_date.value, 7, 4) || '-' || substr(finish_date.value, 4, 2) || '-' || substr(finish_date.value, 1, 2)) >= DATE('2020-01-02')
AND status NOT IN ("closed", "suspended")) , 0) UNION ALL
.......etc
....................................

Answer 1

Use a recursive CTE which returns all the dates of 2020, cross join it to your query and group by each date:
with recursive days as (
select date('2020-01-01') date
union all
select date(date, '+1 day')
from days
where strftime('%Y', date, '+1 day') = '2020'
)
SELECT days.date, COALESCE(SUM(CAST(pc_loading.value AS INT)), 0)
FROM days
CROSS JOIN ticket
JOIN ticket_custom start_date ON (ticket.id = start_date.ticket AND start_date.name = 'planned_start_date')
JOIN ticket_custom finish_date ON (ticket.id = finish_date.ticket AND finish_date.name = 'planned_finish_date')
JOIN ticket_custom pc_loading ON (ticket.id = pc_loading.ticket AND pc_loading.name = 'percentage_loading')
WHERE UPPER(ticket.owner)='#########' AND ticket.type = 'Internal Resource'
AND DATE(substr(start_date.value, 7, 4) || '-' || substr(start_date.value, 4, 2) || '-' || substr(start_date.value, 1, 2)) <= days.date
AND DATE(substr(finish_date.value, 7, 4) || '-' || substr(finish_date.value, 4, 2) || '-' || substr(finish_date.value, 1, 2)) >= days.date
AND status NOT IN ("closed", "suspended")
GROUP BY days.date
Also, you would find significant improvement in performance if you stored the dates in a comparable format like YYYY-MM-DD since there would be no need for all these rearrangements/concatenations in the WHERE clause.
Alternative without the use of the CTE:
SELECT days.date, COALESCE(SUM(CAST(pc_loading.value AS INT)), 0)
FROM (
SELECT '2020-01-01' date UNION ALL SELECT '2020-01-02' UNION ALL
SELECT '2020-01-03' UNION ALL SELECT '2020-01-04' UNION ALL
............................................................
) days
CROSS JOIN ticket
JOIN ticket_custom start_date ON (ticket.id = start_date.ticket AND start_date.name = 'planned_start_date')
JOIN ticket_custom finish_date ON (ticket.id = finish_date.ticket AND finish_date.name = 'planned_finish_date')
JOIN ticket_custom pc_loading ON (ticket.id = pc_loading.ticket AND pc_loading.name = 'percentage_loading')
WHERE UPPER(ticket.owner)='#########' AND ticket.type = 'Internal Resource'
AND DATE(substr(start_date.value, 7, 4) || '-' || substr(start_date.value, 4, 2) || '-' || substr(start_date.value, 1, 2)) <= days.date
AND DATE(substr(finish_date.value, 7, 4) || '-' || substr(finish_date.value, 4, 2) || '-' || substr(finish_date.value, 1, 2)) >= days.date
AND status NOT IN ("closed", "suspended")
GROUP BY days.date