Generate a table with a range of timestamps - Oracle SQL - sql

Question

I am trying to create a table with 2 columns in the below format with all the dates of 2019:-
START_TIME END_TIME
2010-01-01 17:00:00|2019-01-02 17:00:00
2019-01-02 17:00:00|2019-01-03 17:00:00
2019-01-03 17:00:00|2019-01-04 17:00:00
...
...
2019-12-31 17:00:00|2020-01-01 17:00:00
Could you please help troubleshoot the error in this?
Please suggest any optimized way of achieving this.
CREATE TABLE s.dates_2019
(
ts_range_begin timestamp(6),
ts_range_end timestamp(6),
);
insert into s.dates_2019 (ts_range_begin)
select
to_timestamp('12/31/2018 05:00 PM', 'YYYY-MM-DD HH24:MI:SS') + n.n
from
(select rownum n
from ( select 1 just_a_column
from dual
connect by level <=
to_timestamp('12/31/2019 05:00 PM', 'YYYY-MM-DD HH24:MI:SS')
- to_timestamp('12/31/2018 05:00 PM', 'YYYY-MM-DD HH24:MI:SS')
+ 1
) t
) n
where
to_timestamp('12/31/2018 05:00 PM','YYYY-MM-DD HH24:MI:SS') + n.n <= to_timestamp('12/31/2019 05:00 PM','YYYY-MM-DD HH24:MI:SS')
insert into s.dates_2019 (ts_range_end)
select
to_timestamp('2019-01-01 05:00 PM', 'YYYY-MM-DD HH24:MI:SS') + n.n
from
(select rownum n
from ( select 1 just_a_column
from dual
connect by level <=
to_timestamp('2020-01-01 05:00 PM', 'YYYY-MM-DD HH24:MI:SS')
- to_timestamp('2019-01-01 05:00 PM', 'YYYY-MM-DD HH24:MI:SS')
+ 1
) t
) n
where
to_timestamp('2019-01-01 05:00 PM','YYYY-MM-DD HH24:MI:SS') + n.n <= to_timestamp('2020-01-01 05:00 PM','YYYY-MM-DD HH24:MI:SS')
Error is :-
[Error Code: 30081, SQL State: 99999] ORA-30081: invalid data type for datetime/interval arithmetic

Answer 1

How about this?
SQL> alter session set nls_date_format = 'yyyy-mm-dd hh24:mi';
Session altered.
SQL> with dates as
2 (select date '2019-01-01' + 17/24 + level - 1 datum
3 from dual
4 connect by level <= date '2020-01-01' - date '2019-01-01' + 1
5 ),
6 staend as
7 (select datum as start_time,
8 lead(datum) over (order by datum) as end_time
9 from dates
10 )
11 select start_time,
12 end_time
13 from staend
14 where end_time is not null
15 order by start_time;
START_TIME END_TIME
---------------- ----------------
2019-01-01 17:00 2019-01-02 17:00
2019-01-02 17:00 2019-01-03 17:00
2019-01-03 17:00 2019-01-04 17:00
2019-01-04 17:00 2019-01-05 17:00
<snip>
2019-12-30 17:00 2019-12-31 17:00
2019-12-31 17:00 2020-01-01 17:00
365 rows selected.
SQL>
If you want to insert dates into a table, you don't really need a timestamp - date will do.
SQL> create table dates_2019
2 (ts_range_begin date,
3 ts_range_end date
4 );
Table created.
SQL> insert into dates_2019 (ts_range_begin, ts_range_end)
2 with dates as
3 (select date '2019-01-01' + 17/24 + level - 1 datum
4 from dual
5 connect by level <= date '2020-01-01' - date '2019-01-01' + 1
6 ),
7 staend as
8 (select datum as start_time,
9 lead(datum) over (order by datum) as end_time
10 from dates
11 )
12 select start_time,
13 end_time
14 from staend
15 where end_time is not null
16 order by start_time;
365 rows created.
SQL>
If you want to aggregate weekends, consider using offset in the lead analytic function. That offset depends on day name (Friday). Also, remove weekend days from the result set (line #21, where day not in ('sat', 'sun')).
SQL> insert into dates_2019 (ts_range_begin, ts_range_end)
2 with dates as
3 (select date '2019-01-01' + 17/24 + level - 1 datum,
4 --
5 to_char(date '2019-01-01' + 17/24 + level - 1,
6 'fmdy', 'nls_date_language = english') day
7 from dual
8 connect by level <= date '2020-01-01' - date '2019-01-01' + 1
9 ),
10 staend as
11 (select datum as start_time,
12 day,
13 lead(datum, case when day = 'fri' then 3
14 else 1
15 end) over (order by datum) as end_time
16 from dates
17 )
18 select start_time,
19 end_time
20 from staend
21 where day not in ('sat', 'sun')
22 and end_time is not null;
261 rows created.
SQL> select * from dates_2019 order by ts_range_begin;
TS_RANGE_BEGIN TS_RANGE_END
---------------- ----------------
2019-01-01 17:00 2019-01-02 17:00
2019-01-02 17:00 2019-01-03 17:00
2019-01-03 17:00 2019-01-04 17:00
2019-01-04 17:00 2019-01-07 17:00 --> aggregated
2019-01-07 17:00 2019-01-08 17:00
2019-01-08 17:00 2019-01-09 17:00
2019-01-09 17:00 2019-01-10 17:00
2019-01-10 17:00 2019-01-11 17:00
2019-01-11 17:00 2019-01-14 17:00 --> aggregated
2019-01-14 17:00 2019-01-15 17:00
2019-01-15 17:00 2019-01-16 17:00
<snip>

Answer 2

I think your actual error is because subtracting timestamps returns an interval, whereas you're using the result as a number in CONNECT BY LEVEL. You could cast the timestamps as dates (you might find the answers here useful) or use an interval expression to get the day component between the timestamps.
But if this is your actual SQL and not a simplification, I suggest just using dates in the CONNECT BY (you can still keep timestamps in your table if that's what you want) and doing something like...
CREATE TABLE dates_2019
(
ts_range_begin timestamp(6),
ts_range_end timestamp(6)
);
insert into dates_2019 (ts_range_begin)
select
to_timestamp('2018-12-31 17', 'YYYY-MM-DD HH24') + rownum
from
dual
connect by level <= to_date('2019-12-31 17', 'YYYY-MM-DD HH24') - to_date('2018-12-31 17', 'YYYY-MM-DD HH24')
;
update dates_2019 SET ts_range_end = ts_range_begin + 1;
... which I tested in Oracle 18c, but probably works 10g.