Insert records for 40years in table only date - sql

Question

I need to insert only date into a table MONTH_YEAR from 01-01-2010 to 01-01-2040:
For example, I need to insert record on my table month wise
DATE:
01-01-2010
01-02-2010
01-03-2010
01-04-2010
01-05-2010
01-06-2010
01-07-2010
01-08-2010
01-09-2010
01-10-2010
01-11-2010
01-12-2010
01-01-2011
01-02-2011
01-03-2011
01-04-2011
01-05-2011
.....................................
01-06-2040
01-07-2040
01-08-2040
01-09-2040
01-10-2040
01-11-2040
01-12-2040
Like this I want to insert only date into my table for month wise from 01-01-2010 to 01-01-2040

Answer 1

You can use a hierarchical query:
INSERT INTO month_year (column_name)
SELECT ADD_MONTHS(DATE '2010-01-01', LEVEL - 1)
FROM DUAL
CONNECT BY LEVEL <= 31*12;
Or a recursive query:
INSERT INTO month_year (column_name)
WITH range (dt) AS (
SELECT DATE '2010-01-01' FROM DUAL
UNION ALL
SELECT ADD_MONTHS(dt, 1)
FROM range
WHERE dt < DATE '2040-12-01'
)
SELECT dt FROM range;
db<>fiddle here

Answer 2

Row generator it is:
SQL> insert into month_year (datum)
2 select date '2010-01-01' + level - 1
3 from dual
4 connect by level <= date '2040-01-01' - date '2010-01-01' + 1;
10958 rows created.
SQL> select min(datum) min_date,
2 max(datum) max_date
3 from month_year;
MIN_DATE MAX_DATE
---------- ----------
01.01.2010 01.01.2040
SQL>
If you only need 1st of every month, then
SQL> insert into month_year (datum)
2 select add_months(date '2010-01-01', level - 1)
3 from dual
4 connect by level <= months_between(date '2040-01-01', date '2010-01-01') + 1;
361 rows created.
SQL>

Answer 3

Do you really need 40 years of dates, it seems unlikely or can you make due with a virtual calendar, where you specify a start and end_date and all the dates are generated for you. This example does every day in the range but feel free to modify it to produce what you need. I use it in several places.
CREATE OR REPLACE TYPE nt_date IS TABLE OF DATE;
CREATE OR REPLACE FUNCTION generate_dates_pipelined(
p_from IN DATE,
p_to IN DATE
)
RETURN nt_date PIPELINED DETERMINISTIC
IS
v_start DATE := TRUNC(LEAST(p_from, p_to));
v_end DATE := TRUNC(GREATEST(p_from, p_to));
BEGIN
LOOP
PIPE ROW (v_start);
EXIT WHEN v_start >= v_end;
v_start := v_start + INTERVAL '1' DAY;
END LOOP;
RETURN;
END generate_dates_pipelined;
/