Is there any alternative to use MYSQL's ADDDATE() in ORACLE? - sql

Question

I have this query that needs to be executed for oracle sql instead of mysql which is where it originally came from, but I have the ADDDATE() function which I don't see any other alternative than DateAdd since it needs more parameters than I really need..
Apart from that, if I try to execute it, it also indicates an error in the
SELECT 0 i UNION.................
part, saying the following ORA-00923: FROM keyword not found where expected
Maybe in oracle it is not allowed to do a select 0 union select 1 union...
Any suggestions or help I appreciate it, thanks
SELECT
ADDDATE('1970-01-01', t4.i * 10000 + t3.i * 1000 + t2.i * 100 + t1.i * 10 + t0.i) selected_date
FROM
(
SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9
) t0,
(
SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9
) t1,
(
SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9
) t2,
(
SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9
) t3,
(
SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9
) t4

Answer 1

In Oracle you must select from the one-row table dual in order to select one row. You cannot select without a from clause.
If you want to generate dates, you'll write a standard SQL recursive CTE. (And this is the typical approach now in MySQL, too, since version 8.0.)
Here is an example selecting all days for 1970:
with dates (dt) as
(
select date '1970-01-01' from dual
union all
select dt + interval '1' day from dates where dt < date '1970-12-31'
)
select dt from dates;

Answer 2

Here is another way to SELECT a list of dates for the year 1970. Adjust the starting and ending dates if you want different years or the INTERVAL if you want different periods like seconds, minutes, hours…
ALTER SESSION SET NLS_DATE_FORMAT = 'DD-MON-YYYY HH24:MI:SS';
with dt (dt, interv) as (
select date '1970-01-01', numtodsinterval(1,'DAY') from dual
union all
select dt.dt + interv, interv from dt
where dt.dt + interv <= date '1970-12-31')
select dt from dt;
/