Closest Date to a given date - SQL Oracle - sql

Question

Oracle (SQL) - I have 3 available dates in a month (1st, 10th and 25th). I need a query to find out the closest among the 3 dates based on the date of executing my query. For e.g, when i run the query on 4th, i should get 10th as my result, when i run on 12th, the result should be 25th and when i run on 27th, the result should be the 01st of next month.
I am struggling with the logic. Please help..

Answer 1

with
inputs ( dt ) as (
select to_date( '03/24/2015 11:30:00', 'mm/dd/yyyy hh24:mi:ss') from dual union all
select to_date( '08/03/2016 07:15:00', 'mm/dd/yyyy hh24:mi:ss') from dual union all
select to_date( '02/29/2016 22:30:00', 'mm/dd/yyyy hh24:mi:ss') from dual
)
-- End of simulated inputs (for testing only, not part of the solution).
-- SQL query begins BELOW THIS LINE. Use your actual table and column names.
select dt,
case when extract(day from dt) < 10 then trunc(dt, 'mm') + interval '9' day
when extract(day from dt) < 25 then trunc(dt, 'mm') + interval '24' day
else add_months(trunc(dt, 'mm'), 1)
end as next_std_dt
from inputs;
DT NEXT_STD_DT
------------------- -------------------
03/24/2015 11:30:00 03/25/2015 00:00:00
08/03/2016 07:15:00 08/10/2016 00:00:00
02/29/2016 22:30:00 03/01/2016 00:00:00

Answer 2

I believe this is much more efficient and simpler than the other solutions.
WITH
possible_dates
AS
-- generate the three available dates for the current month
(SELECT TRUNC (SYSDATE, 'MM') available_date
FROM DUAL
UNION ALL
SELECT TRUNC (SYSDATE, 'MM') + 9
FROM DUAL
UNION ALL
SELECT TRUNC (SYSDATE, 'MM') + 24
FROM DUAL
UNION ALL
SELECT ADD_MONTHS (TRUNC (SYSDATE, 'MM'), 1)
FROM DUAL),
delta
AS
-- calculate the distance of those available dates
(SELECT (available_date - SYSDATE) diff, available_date
FROM possible_dates)
SELECT *
FROM delta
WHERE diff = (SELECT MIN (diff)
FROM delta
WHERE diff >= 0);

Answer 3

If using PL SQL is an option, then use the query as following:
`DECLARE
curr_month CHAR(2);
curr_year CHAR(4);
future_date DATE;
BEGIN
select to_char(sysdate, 'MM') INTO curr_month from dual;
select to_char(sysdate, 'YYYY') INTO curr_year from dual;
future_date := TO_DATE('12' || curr_month || curr_year, 'DD/MM/YYYY');
IF (SYSDATE > future_date) THEN
{..whatever you want to do...}
ELSIF (SYSDATE > future_date2) THEN
{..whatever you want to do...}
END IF;
END;`

Answer 4

WITH mytable(dt) AS
(SELECT '01'
FROM dual
UNION ALL SELECT '10'
FROM dual
UNION ALL SELECT '25'
FROM dual),
given_dates AS
(SELECT Trunc (To_date (dt || To_char(sysdate, 'MMYYYY'), 'DDMMYYYY')) dt,
Trunc(sysdate) cdate
FROM mytable),
comp AS
(SELECT cdate,
CASE
WHEN ABS (cdate - dt) < ABS (cdate - Add_months (dt, 1)) THEN dt
ELSE Add_months (dt, 1)
END dt_comp
FROM given_dates)
SELECT dt_comp closest_date
FROM
(SELECT dt_comp,
rank() OVER (
ORDER BY ABS (cdate - dt_comp)) rn
FROM comp)
WHERE rn = 1;