Generating sequence skipping by 2 Oracle - sql

Question

I have the below query.But I want to tweak the output to skip 2 consecutive numbers on every cycle.
For example skip 1,2 in 2nd cycle . Skip 3,4 in 3rd cycle . Skip 5,6 in 4th cycle and so on.
Also, there will be 2 input variables (i) the number to be removed/added (ii) from which date.
Once this is passed the sequence will have to be recalculate from that date on wards.
I am using Oracle version 12.1
SELECT TRUNC(sysdate, 'Y') + level - 1 AS "date", MOD(level - 1, 10) + 1 AS col1
FROM dual
CONNECT BY level <= ADD_MONTHS(TRUNC(sysdate, 'Y'), 12) - TRUNC(sysdate, 'Y')
Date Col1 Expected Output
1/1/2022 1 1
1/2/2022 2 2
1/3/2022 3 3
1/4/2022 4 4
1/5/2022 5 5
1/6/2022 6 6
1/7/2022 7 7
1/8/2022 8 8
1/9/2022 9 9
1/10/2022 10 10
1/11/2022 1 3
1/12/2022 2 4
1/13/2022 3 5
1/14/2022 4 6
1/15/2022 5 7
1/16/2022 6 8
1/17/2022 7 9
1/18/2022 8 10
1/19/2022 9 1
1/20/2022 10 2
1/21/2022 1 5
1/22/2022 2 6
1/23/2022 3 7
1/24/2022 4 8
1/25/2022 5 9
1/26/2022 6 10
1/27/2022 7 1
1/28/2022 8 2
1/29/2022 9 3
1/30/2022 10 4
1/31/2022 1 7
2/1/2022 2 8
2/2/2022 3 9
2/3/2022 4 10

Answer 1

You can use some more arithmetical functions such as FLOOR() and CEIL() along with precomputing unmatched values within a subquery, and then filter out by the incremented values upto the currently existing expression's value of
ADD_MONTHS(TRUNC(sysdate, 'Y'), 12) - TRUNC(sysdate, 'Y')
such as
WITH d AS
(
SELECT SUM(CASE
WHEN MOD(FLOOR((level-.1)/10),6) = CEIL((MOD(level - 1, 10) + 1)/2)
THEN
0
ELSE
1
END)
OVER (ORDER BY level) AS rn,
ADD_MONTHS(TRUNC(sysdate, 'Y'), 12) - TRUNC(sysdate, 'Y') AS day_diff,
MOD(level - 1, 10) + 1 AS col1,
MOD(FLOOR((level-.1)/10),6) AS col2,
CEIL((MOD(level - 1, 10) + 1)/2) AS col3
FROM dual
CONNECT BY level <= (ADD_MONTHS(TRUNC(sysdate, 'Y'), 12) - TRUNC(sysdate, 'Y'))*2
)
SELECT TRUNC(sysdate, 'Y') + rn - 1 AS "date", col1
FROM d
WHERE col2 != col3
AND rn <= day_diff
ORDER BY rn
Demo

Answer 2

Wrote below . Thanks for your answer as well. I just made some columns in excel and wrote some functions to get it
WITH Y AS
(SELECT TRUNC(SYSDATE, 'Y') + LEVEL - 1 dt,
MOD(LEVEL - 1, 10) + 1 AS grpid,
LEVEL rnum
FROM dual
CONNECT BY LEVEL <=
ADD_MONTHS(TRUNC(SYSDATE, 'Y'), 12) - TRUNC(SYSDATE, 'Y')),
Z AS
(SELECT dt,
rnum,
COUNT(CASE
WHEN grpid = 1 THEN
1
END) OVER(ORDER BY dt) - 1 as grp
FROM y)
SELECT z.*,
REGEXP_REPLACE(CASE
WHEN MOD(rnum, grp * 10) = 1 THEN
MOD(grp + grp + 1, 10)
WHEN MOD(rnum, grp * 10) = 2 THEN
MOD(grp + grp + 2, 10)
ELSE
MOD(rnum - grp * (10 - 2), 10)
END,
'^0$',
10) output
FROM Z;