How to extract timestamp differences in hours and do cumulative sum - sql

Question

CREATE TABLE test (
id NUMBER(10),
due_dt TIMESTAMP(6),
status VARCHAR2(10),
created_on TIMESTAMP(6),
act_taken_on TIMESTAMP(6)
);
insert into test values(1,'21-SEP-22 02.53.10.016537 AM','created','19-SEP-22 02.53.10.016537 AM','20-SEP-22 02.53.10.016537 AM');
insert into test values(1,'21-SEP-22 02.53.10.016537 AM','created','20-SEP-22 02.53.10.016537 AM','21-SEP-22 02.53.10.016537 AM');
insert into test values(2,'21-SEP-22 02.53.10.016537 AM','Approved','21-SEP-22 02.53.10.016537 AM','22-SEP-22 02.53.10.016537 AM');
DB Version: Oracle SQL Developer 18c
I have one table from which I need to calculate the difference between the timestamp and need to show only the hours differences. As per the below explanation:
Need to populate below columns:
aging : When status is created then take differences between created_on and act_taken_on and it should show only the hours differences. If the id is repeating then it should sum up with the previous value.
In my sample data set for the id 1 there are two rows so the for the first row aging column will be 24 hrs approx. and for the next id 1 it should sum up with the previous value which is 24 hrs and give the result as 48 hrs approx.
time_left: difference between due_dt and sysdate and should show differences only in hours.
My attempt:
SELECT id,
CASE
when status = 'created' then (created_on - act_taken_on)
when status = 'Approved' then (created_on - act_taken_on)
end aging,
(due_dt - sysdate) time_left
from test;
Expected output:
+----+---------+-----------+
| id | Aging | time_left |
+----+---------+-----------+
| 1 | 24Hours | 48hours |
| 1 | 48Hours | 48Hours |
| 2 | 24Hours | 48Hours |
+----+---------+-----------+

Answer 1

Here's one option, which casts timestamps as date as you only need rounded hours and uses sum function in its analytic form.
Sample data:
SQL> select * from test order by id, created_on;
ID DUE_DT STATUS CREATED_ON ACT_TAKEN_ON
--- ------------------------- ---------- ------------------------- -------------------------
1 21.09.22 02:53:10,016537 created 19.09.22 02:53:10,016537 20.09.22 02:53:10,016537
1 21.09.22 02:53:10,016537 created 20.09.22 02:53:10,016537 21.09.22 02:53:10,016537
2 21.09.22 02:53:10,016537 Approved 21.09.22 02:53:10,016537 22.09.22 02:53:10,016537
Right now is
SQL> select sysdate from dual;
SYSDATE
-------------------
19.09.2022 13.17:07
Query:
SQL> select id,
2 round (
3 sum (
4 (cast (act_taken_on as date) - cast (created_on as date)) * 24)
5 over (partition by id order by created_on),
6 0) aging,
7 round ((cast (due_dt as date) - sysdate) * 24, 0) time_left
8 from test;
ID AGING TIME_LEFT
--- ---------- ----------
1 24 38
1 48 38
2 24 38
SQL>
As you commented that you'd want to include CASE expression that regards the status column (but you're getting some errors), I'm not sure what exactly you meant to do with that, but - here's how (time_left has changed as sysdate now returns 20.09.2022 07:02):
SQL> select id,
2 sum (
3 case
4 when status = 'created'
5 then
6 (cast (act_taken_on as date) - cast (created_on as date))
7 * 24
8 when status = 'Approved'
9 then
10 (cast (act_taken_on as date) - cast (created_on as date))
11 * 24
12 end)
13 over (partition by id order by created_on) aging,
14 round ((cast (due_dt as date) - sysdate) * 24, 0) time_left
15 from test;
ID AGING TIME_LEFT
---------- ---------- ----------
1 24 20
1 48 20
2 24 20
SQL>

Answer 2

Convert your TIMESTAMP values to DATEs, then subtract them and take the FLOOR (that is, round down).
When you subtract one DATE from another you get a floating-point value that's the difference between them in calendar days.
Like this:
FLOOR(24*(CAST(due_dt AS DATE) - CAST(created_on AS DATE)))