Date Transformation using Hive or sql - sql

Question

Premise: You have a table with one column, original_date, of datatype string:
ORIGINAL_DATE
20190825
20190826
20190827
20190828
20190829
20190830
20190831
20190901
Question: Write a SQL query to calculate two more columns – end_of_week - the date of the next Sunday from original_date. If original_date is already a Sunday, this field should be the same value end_of_month - the value of the end of month date An acceptable solution is one which works for any valid date in the string format of original_date. With end_of_month and end_of_week computed
ORIGINAL_DATE END_OF_WEEK END_OF_MONTH
20190825 20190825 20190831
20190826 20190901 20190831
20190827 20190901 20190831
20190828 20190901 20190831
20190829 20190901 20190831
20190830 20190901 20190831
20190831 20190901 20190831
20190901 20190901 20190930
Additional Info:
20190825 is a Sunday, so the end_of_week for that value is still that same date.
20190827 is a Tuesday, and the next Sunday is on 20190901
CREATE TABLE random_dates ( original_date VARCHAR(8) NOT NULL );
INSERT INTO random_dates(original_date) values('20190825');
INSERT INTO random_dates(original_date) values('20190826');
INSERT INTO random_dates(original_date) values('20190827');
INSERT INTO random_dates(original_date) values('20190828');
INSERT INTO random_dates(original_date) values('20190829');
INSERT INTO random_dates(original_date) values('20190830');
INSERT INTO random_dates(original_date) values('20190831');
INSERT INTO random_dates(original_date) values('20190901');
EXPECTED OUTPUT:
20190825 2019-08-25 2019-08-31
20190826 2019-09-01 2019-08-31
20190827 2019-09-01 2019-08-31
20190828 2019-09-01 2019-08-31
20190829 2019-09-01 2019-08-31
20190830 2019-09-01 2019-08-31
20190831 2019-09-01 2019-08-31
20190901 2019-09-01 2019-09-30

Answer 1

Solution for Hive:
with random_dates as (--this is your example dataset
select stack(8,
'20190825', '20190826', '20190827', '20190828', '20190829', '20190830', '20190831', '20190901'
) as original_date
)
select original_date,
date_add(date_formatted, 6-days) end_of_week,
last_day(date_formatted) end_of_month
from
(
select original_date,
regexp_replace(original_date,'^(\\d{4})(\\d{2})(\\d{2})$','$1-$2-$3') date_formatted,
pmod(datediff(regexp_replace(original_date,'^(\\d{4})(\\d{2})(\\d{2})$','$1-$2-$3'),'1900-01-08'),7) days
from random_dates
)s
;
Result:
original_date end_of_week end_of_month
20190825 2019-08-25 2019-08-31
20190826 2019-09-01 2019-08-31
20190827 2019-09-01 2019-08-31
20190828 2019-09-01 2019-08-31
20190829 2019-09-01 2019-08-31
20190830 2019-09-01 2019-08-31
20190831 2019-09-01 2019-08-31
20190901 2019-09-01 2019-09-30

Answer 2

SELECT original_date,
CASE DAYOFWEEK(STR_TO_DATE(original_date,'%Y%m%d'))
WHEN 1 THEN DATE_ADD(STR_TO_DATE(original_date,'%Y%m%d'),INTERVAL 0 DAY)
WHEN 2 THEN DATE_ADD(STR_TO_DATE(original_date,'%Y%m%d'),INTERVAL 6 DAY)
WHEN 3 THEN DATE_ADD(STR_TO_DATE(original_date,'%Y%m%d'),INTERVAL 5 DAY)
WHEN 4 THEN DATE_ADD(STR_TO_DATE(original_date,'%Y%m%d'),INTERVAL 4 DAY)
WHEN 5 THEN DATE_ADD(STR_TO_DATE(original_date,'%Y%m%d'),INTERVAL 3 DAY)
WHEN 6 THEN DATE_ADD(STR_TO_DATE(original_date,'%Y%m%d'),INTERVAL 2 DAY)
WHEN 7 THEN DATE_ADD(STR_TO_DATE(original_date,'%Y%m%d'),INTERVAL 1 DAY)
END AS END_OF_WEEK,
LAST_DAY(STR_TO_DATE(original_date,'%Y%m%d')) AS END_OF_MONTH
FROM random_dates;