Split single row into multiple rows based on week of the month in date - sql

Question

I have a table like this
Id Valid_From Valid_To
9744 24/06/2019 07/07/2019
9745 12/08/2019 31/12/9999
I would like to split this table into multiple rows based on the week like this by joining to the date table
Id Valid_from Valid_To Month Week
9744 24/06/2019 07/07/2019 June 4
9744 24/06/2019 07/07/2019 July 1
9744 24/06/2019 07/07/2019 July 2
9745 12/08/2019 31/12/9999 August 2
9745 12/08/2019 31/12/9999 August 3
9745 12/08/2019 31/12/9999 August 4
In this case there will be 3 rows as the valid from and valid two falls between these 3 weeks for ID - 9744
For ID - 9745 the Valid_to date is infinity so we need to just take all the week in the current month from the valid_from date
I then just need to append the output with Month and the Week number
Can someone help me to write a query to have this output?
Thanks

Answer 1

You mention a "date" table. If you have one then you can use a join like this:
select distinct t.id, valid_from, t.valid_to, d.month, d.week
from yourtable t join
date d
on d.date >= t.valid_from and
d.date <= t.valid_to;

Answer 2

If I understand your question right, you need to list all month names and week numbers of these months' existing between valid_from and valid_to dates. I did it by following query:
SELECT
Q.ID,
Q.VALID_FROM,
Q.VALID_TO,
Q.MONTH_NAME,
WEEK_NUMBER
FROM
(
SELECT
CEIL((Q.DATES_BETWEEN_INTERVAL - FIRST_DAY_OF_MONTH + 1) / 7) WEEK_NUMBER,
TO_CHAR(Q.DATES_BETWEEN_INTERVAL, 'MONTH', 'NLS_DATE_LANGUAGE = American') MONTH_NAME,
Q.*
FROM
(
SELECT
LEVEL + S.VALID_FROM DATES_BETWEEN_INTERVAL,
TRUNC(LEVEL + S.VALID_FROM, 'MONTH') FIRST_DAY_OF_MONTH,
S.* FROM
(
SELECT T.*,
(CASE WHEN EXTRACT(YEAR FROM T.VALID_TO) = 9999 THEN LAST_DAY(T.VALID_FROM) ELSE T.VALID_TO END) - T.VALID_FROM DAYS_COUNT
FROM AAA_TABLE T
) S
CONNECT BY LEVEL <= S.DAYS_COUNT
) Q
) Q
GROUP BY
Q.ID,
Q.VALID_FROM,
Q.VALID_TO,
Q.MONTH_NAME,
WEEK_NUMBER
ORDER BY
Q.ID,
Q.VALID_FROM,
Q.VALID_TO,
Q.MONTH_NAME,
WEEK_NUMBER;
But there must be 5th week if the date greater than 28th day of month. Hope this will help you.