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

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.