Oracle SQL Developer Subscriber - Creating a Cross Table - sql

Question

I have a table UPCALL_HISTORY that has 3 columns: SUBSCRIBER_ID, START_DATE and END_DATE. Let the number of unique subscribers be N.
I want to create a new table with 3 columns:
SUBSCRIBER_ID: All of the unique subscriber ids repeated 36 times in a row.
MONTHLY_CALENDAR_ID: For each SUBSCRIBER_ID, this column will have dates listed from July 2015 until July 2018 (36 months).
ACTIVE: This column will be used as a flag for each subscriber and whether they have a subscription during that month. This subscription data is in a table called UPCALL_HISTORY.
I am fairly new to SQL, don't have a lot of experience. I am good at Python but it seems that SQL doesn't work like Python.
Any query ideas that could help me build this table?
Let my UPCALL_HISTORY table be:
+---------------+------------+------------+
| SUBSCRIBER_ID | START_DATE | END_DATE |
+---------------+------------+------------+
| 119 | 01/07/2015 | 01/08/2015 |
| 120 | 01/08/2015 | 01/09/2015 |
| 121 | 01/09/2015 | 01/10/2015 |
+---------------+------------+------------+
I want a table that looks like:
+---------------+------------+--------+
| SUBSCRIBER_ID | MON_CA | ACTIVE |
+---------------+------------+--------+
| 119 | 01/07/2015 | 1 |
| * | 01/08/2015 | 0 |
| * | 01/09/2015 | 0 |
| (36 times) | 01/10/2015 | 0 |
| * | * | 0 |
| 119 | 01/07/2018 | 0 |
+---------------+------------+--------+
that continues for 120 and 121
EDIT: Added Example

Answer 1

Here's how I understood the question.
Sample table and several rows:
SQL> create table upcall_history
2 (subscriber_id number,
3 start_date date,
4 end_date date);
Table created.
SQL> insert into upcall_history
2 select 1, date '2015-12-25', date '2016-01-13' from dual union
3 select 1, date '2017-07-10', date '2017-07-11' from dual union
4 select 2, date '2018-01-01', date '2018-04-24' from dual;
3 rows created.
Create a new table. For distinct SUBSCRIBER_ID's, it creates 36 "monthly" rows, fixed (as you stated).
SQL> create table new_table as
2 select
3 x.subscriber_id,
4 add_months(date '2015-07-01', column_value - 1) monthly_calendar_id,
5 0 active
6 from (select distinct subscriber_id from upcall_history) x,
7 table(cast(multiset(select level from dual
8 connect by level <= 36
9 ) as sys.odcinumberlist));
Table created.
Update ACTIVE column value to "1" for rows whose MONTHLY_CALENDAR_ID is contained in START_DATE and END_DATE of the UPCALL_HISTORY table.
SQL> merge into new_table n
2 using (select subscriber_id, start_date, end_date from upcall_history) x
3 on ( n.subscriber_id = x.subscriber_id
4 and n.monthly_calendar_id between trunc(x.start_date, 'mm')
5 and trunc(x.end_date, 'mm')
6 )
7 when matched then
8 update set n.active = 1;
7 rows merged.
SQL>
Result (only ACTIVE = 1):
SQL> select * from new_table
2 where active = 1
3 order by subscriber_id, monthly_calendar_id;
SUBSCRIBER_ID MONTHLY_CA ACTIVE
------------- ---------- ----------
1 2015-12-01 1
1 2016-01-01 1
1 2017-07-01 1
2 2018-01-01 1
2 2018-02-01 1
2 2018-03-01 1
2 2018-04-01 1
7 rows selected.
SQL>

Answer 2

If you're on 12c you can use an inline view of all the months with cross apply to get the combinations of those with all IDs:
select uh.subscriber_id, m.month,
case when trunc(uh.start_date, 'MM') <= m.month
and (uh.end_date is null or uh.end_date >= add_months(m.month, 1))
then 1 else 0 end as active
from upcall_history uh
cross apply (
select add_months(trunc(sysdate, 'MM'), - level) as month
from dual
connect by level <= 36
) m
order by uh.subscriber_id, m.month;
I've made it a rolling 36-months window up to the current month, but you may actually want fixed dates as you had in the question.
With sample data from a CTE:
with upcall_history (subscriber_id, start_date, end_date) as (
select 1, date '2015-09-04', '2015-12-15' from dual
union all select 2, date '2017-12-04', '2018-05-15' from dual
)
that generates 72 rows:
SUBSCRIBER_ID MONTH ACTIVE
------------- ---------- ----------
1 2015-07-01 0
1 2015-08-01 0
1 2015-09-01 1
1 2015-10-01 1
1 2015-11-01 1
1 2015-12-01 0
1 2016-01-01 0
...
2 2017-11-01 0
2 2017-12-01 1
2 2018-01-01 1
2 2018-02-01 1
2 2018-03-01 1
2 2018-04-01 1
2 2018-05-01 0
2 2018-06-01 0
You can use that to create a new table, or populate an existing table; though if you do want a rolling window then a view might be more appropriate.
If you aren't on 12c then cross apply isn't available - you'll get "ORA-00905: missing keyword".
You can get the same result with two CTEs (one to get all the months, the other to get all the IDs) cross-joined, and then outer joined to your actual data:
with m (month) as (
select add_months(trunc(sysdate, 'MM'), - level)
from dual
connect by level <= 36
),
i (subscriber_id) as (
select distinct subscriber_id
from upcall_history
)
select i.subscriber_id, m.month,
case when uh.subscriber_id is null then 0 else 1 end as active
from m
cross join i
left join upcall_history uh
on uh.subscriber_id = i.subscriber_id
and trunc(uh.start_date, 'MM') <= m.month
and (uh.end_date is null or uh.end_date >= add_months(m.month, 1))
order by i.subscriber_id, m.month;

Answer 3

You can do this in 11g using Partitioned Outer Joins, like so:
WITH upcall_history AS (SELECT 119 subscriber_id, to_date('01/07/2015', 'dd/mm/yyyy') start_date, to_date('01/08/2015', 'dd/mm/yyyy') end_date FROM dual UNION ALL
SELECT 120 subscriber_id, to_date('01/08/2015', 'dd/mm/yyyy') start_date, to_date('01/09/2015', 'dd/mm/yyyy') end_date FROM dual UNION ALL
SELECT 121 subscriber_id, to_date('01/09/2015', 'dd/mm/yyyy') start_date, to_date('01/10/2015', 'dd/mm/yyyy') end_date FROM dual),
mnths AS (SELECT add_months(TRUNC(SYSDATE, 'mm'), + 1 - LEVEL) mnth
FROM dual
CONNECT BY LEVEL <= 12 * 3 + 1)
SELECT uh.subscriber_id,
m.mnth,
CASE WHEN mnth BETWEEN start_date AND end_date - 1 THEN 1 ELSE 0 END active
FROM mnths m
LEFT OUTER JOIN upcall_history uh PARTITION BY (uh.subscriber_id) ON (1=1)
ORDER BY uh.subscriber_id,
m.mnth;
SUBSCRIBER_ID MNTH ACTIVE
------------- ----------- ----------
119 01/07/2015 1
119 01/08/2015 0
119 01/09/2015 0
119 01/10/2015 0
<snip>
119 01/06/2018 0
119 01/07/2018 0
--
120 01/07/2015 0
120 01/08/2015 1
120 01/09/2015 0
120 01/10/2015 0
<snip>
120 01/06/2018 0
120 01/07/2018 0
--
121 01/07/2015 0
121 01/08/2015 0
121 01/09/2015 1
121 01/10/2015 0
<snip>
121 01/06/2018 0
121 01/07/2018 0
N.B. I have assumed some things about your start/end dates and what constitutes active; hopefully it should be easy enough for you to tweak the case statement to fit the logic that works best for your situation.

Answer 4

I also believe this is can be an example for CROSS JOIN. All I had to do was create a small table of all of the dates and then CROSS JOIN it with the table of subscribers.
Example: https://www.essentialsql.com/cross-join-introduction/