Calculate total time without vacations in postgres - sql

Question

I have a database table that represents activities and for each activity, how long it took.
It looks something like this :
activity_id | name | status | start_date | end_date
=================================================================
1 | name1 | WIP | 2019-07-24 ... | 2019-07-24 ...
start_date and end_date are timestamps. I use a view with a column total_time that is described like that:
date_part('day'::text,
COALESCE(sprint_activity.end_date::timestamp with time zone, CURRENT_TIMESTAMP)
- sprint_activity.start_date::timestamp with time zone
) + date_part('hour'::text,
COALESCE(sprint_activity.end_date::timestamp with time zone, CURRENT_TIMESTAMP)
- sprint_activity.start_date::timestamp with time zone
) / 24::double precision AS total_time
I would like to create a table for vacation or half day vacations that looks like:
date | work_percentage
=================================================
2019-07-24 | 0.4
2019-07-23 | 0.7
And then, I would like to calculate total_time in a way that uses this vacations table such that:
If a date is not in the column it's considered to have work_percentage==1
For every date that is in the table, reduce the relative percentage from the total_time query.
So let's take an example:
Activity - "Write report" started at 11-July-2019 14:00 and ended at 15-July-2019 19:00 - so the time diff is 4 days and 5 hours.
The 13th and 14th were weekend so I'd like to have a column in the vacations table that holds 2019-07-13 with work_percentage == 1 and the same for the 14th.
Deducting those vacations, the time diff would be 2 days and 5 hours as the 13th and 14th are not workdays.
Hope this example explains it better.

Answer 1

I think you can take this example and add some modifications based on your database
Just ddl statements to test script
create table activities (
user_id int,
activity_id int,
name text,
status text,
start_date timestamp,
end_date timestamp
);
create table vacations (
user_id int,
date date,
work_percentage numeric
);
insert into activities
values
(1, 1, 'name1', 'WIP', timestamp'2019-07-20 10:00:00', timestamp'2019-07-25 8:00:00'),
(2, 2, 'name2', 'DONE', timestamp'2019-07-28 19:00:00', timestamp'2019-08-01 7:00:00'),
(1, 3, 'name3', 'DONE', timestamp'2019-07-21 12:00:00', timestamp'2019-07-21 15:00:00'),
(-1, 4, 'Write report', 'DONE', timestamp'2019-07-11 14:00:00', timestamp'2019-07-15 19:00:00');
insert into vacations
values
(1, date'2019-07-21', 0.5),
(1, date'2019-07-22', 0),
(1, date'2019-07-23', 0.25),
(2, date'2019-07-29', 0),
(2, date'2019-07-30', 0),
(-1, date'2019-07-13', 0),
(-1, date'2019-07-14', 0);
sql script
with
daily_activity as (
select
*,
date(
generate_series(
date(start_date),
date(end_date),
interval'1 day')
) as date_key
from
activities
),
raw_data as (
select
da.*,
v.work_percentage,
case
when date(start_date) = date(end_date)
then (end_date - start_date) * coalesce(work_percentage, 1)
when date(start_date) = date_key
then (date(start_date) + 1 - start_date) * coalesce(work_percentage, 1)
when date(end_date) = date_key
then (end_date - date(end_date)) * coalesce(work_percentage, 1)
else interval'24 hours' * coalesce(work_percentage, 1)
end as activity_coverage
from
daily_activity as da
left join vacations as v on da.user_id = v.user_id
and da.date_key = v.date
)
select
user_id,
activity_id,
name,
status,
start_date,
end_date,
justify_interval(sum(activity_coverage)) as total_activity_time
from
raw_data
group by
1, 2, 3, 4, 5, 6