by 
This week we’re looking at something quirky but useful: date dimension together with a UDF that calculates the number of business days between 2 dates (and because it’s an easy challenge, we’re not excluding holidays).
We’ve talked to the Superhero Union and have received complaints that the schedules for any given hero, doesn’t take into account a ‘normal working routine’ and that ‘even superheroes need weekends off’.
To start this venture, we need you to construct a date dimension table that contains the following :
- the date, starting from 1-1-2000
- The year in 4 numbers (for 1-1-2000 this would be 2000)
- The first 3 letters of the month (for 1-1-2000 this would be Jan)
- The name of the month (for 1-1-2000 this would be January)
- The number of the day within that month (for 1-1-2000 this would be 1)
- The number of the weekday (Mondays are 1, Tuesdays are 2, etc., OR any other order that makes sense to you )
- The number of the week in that year (for 1-1-2000 this would be 1)
- The number of the day in that year (for 1-1-2000 this would be 1)
Besides the date dimension you should also create a function to calculate the number of business days between 2 dates that can easily switch between including or excluding the 2nd date in the calculation (so From and including Monday, 2 November 2020 to, but not including Friday, 6 November 2020 is 4 days
but From and including Monday, 2 November 2020 to and including Friday, 6 November 2020 is 5 days)
THEN use this function on the following testing_data :
testing_data
create table testing_data (
id INT,
start_date DATE,
end_date DATE
);
insert into testing_data (id, start_date, end_date) values (1, '11/11/2020', '9/3/2022');
insert into testing_data (id, start_date, end_date) values (2, '12/8/2020', '1/19/2022');
insert into testing_data (id, start_date, end_date) values (3, '12/24/2020', '1/15/2022');
insert into testing_data (id, start_date, end_date) values (4, '12/5/2020', '3/3/2022');
insert into testing_data (id, start_date, end_date) values (5, '12/24/2020', '6/20/2022');
insert into testing_data (id, start_date, end_date) values (6, '12/24/2020', '5/19/2022');
insert into testing_data (id, start_date, end_date) values (7, '12/31/2020', '5/6/2022');
insert into testing_data (id, start_date, end_date) values (8, '12/4/2020', '9/16/2022');
insert into testing_data (id, start_date, end_date) values (9, '11/27/2020', '4/14/2022');
insert into testing_data (id, start_date, end_date) values (10, '11/20/2020', '1/18/2022');
insert into testing_data (id, start_date, end_date) values (11, '12/1/2020', '3/31/2022');
insert into testing_data (id, start_date, end_date) values (12, '11/30/2020', '7/5/2022');
insert into testing_data (id, start_date, end_date) values (13, '11/28/2020', '6/19/2022');
insert into testing_data (id, start_date, end_date) values (14, '12/21/2020', '9/7/2022');
insert into testing_data (id, start_date, end_date) values (15, '12/13/2020', '8/15/2022');
insert into testing_data (id, start_date, end_date) values (16, '11/4/2020', '3/22/2022');
insert into testing_data (id, start_date, end_date) values (17, '12/24/2020', '8/29/2022');
insert into testing_data (id, start_date, end_date) values (18, '11/29/2020', '10/13/2022');
insert into testing_data (id, start_date, end_date) values (19, '12/10/2020', '7/31/2022');
insert into testing_data (id, start_date, end_date) values (20, '11/1/2020', '10/23/2021');Remember, if you want to participate:
- Sign up as a member of Frosty Friday. You can do this by clicking on the sidebar, and then going to ‘REGISTER‘
- Post your code to GitHub and make it publicly available (Check out our guide if you don’t know how to here)
- Post the URL in the comments of the challenge
12 responses to “Week 19 – Basic”
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This one confused me as I couldn’t figure out what the date scaffold table was actually used for. I still created it though with the code in my solution, which I stole from my recent blog post:
The UDF itself was pretty easy since Python’s Numpy package already has the required functionality
- Solution URL – https://github.com/ChrisHastieIW/Frosty-Friday
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Used the date_spine helper from dbt_utils to create the backbone and added the extra columns. I included an ‘is_holiday’, set to false but that could be overridden with other info.
Then I used the table to compute the days removing sat/sun, holidays,…
UDF – https://github.com/dsmdavid/frostyfridays-sf/blob/main/macros/ch_19_create_udf.sql
Base calendar table https://github.com/dsmdavid/frostyfridays-sf/blob/main/models/challenge_19.sql -
I used an SQL function to calculate the difference of working days. I believe that in this case it is necessary to use the dim date table. If there is a holiday flag in the table, it is possible to include it in the calculation.
- Solution URL – https://github.com/mateusz-kmon/frostyfridaychallenges/blob/main/w19.sql
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My contribution
- Solution URL – https://github.com/isarenz/FrostyFridayChallenges/blob/main/FrostyFriday_Challenge_Week19.sql
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A great refresher for dates and scaffolding
- Solution URL – https://github.com/Atzmonky/snowflake/blob/main/ch_19_dates.sql
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Here’s my solution
- Solution URL – https://github.com/apd-jlaird/frosty-friday/blob/main/week_19/ff_week_19.sql
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Went for the short route for UDF with datediff function.
- Solution URL – https://github.com/zlzlzl2-data/FrostyFriday/blob/main/FF19_LZ.sql
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Learned a lot again, from the challenge, AND from solutions by others…
- Solution URL – https://github.com/arjansnowflake/Frosty_Friday/blob/main/Weekly_19/week_19.sql
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a few ways to tackle this one. Cleanest bit of code I could muster
- Solution URL – https://github.com/NMangera/frosty_friday/blob/main/wk%2019%20-%20basic%20/dates
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I initially made a python udf but it’s just so much cleaner to make use of the dimension table. So I changed it to a SQL udf
- Solution URL – https://github.com/darylkit/Frosty_Friday/blob/main/Week%2019%20-%20Dates/dates.sql
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This is my version of the solution for this task. I hope you find it helpful! ^^
- Solution URL – https://github.com/GerganaAK/FrostyFridays/blob/main/Week%2019%20%E2%80%93%20Basic
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The challenge is very simple, yet profound.
- Solution URL – https://github.com/tomoWakamatsu/FrostyFriday/blob/main/FrostyFriday-Week19.SQL
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