How to get financial quarters date by current date - sql

Question

The quarters described as below:
APRIL - JUNE - Q1
JULY - SEPT - Q2
OCT - DEC - Q3
JAN - MARCH - Q4
For ex:
Date = '2018-12-24' -- Where this date is under third quarter
So Expected should be [Get all quarter < current date's quarter]
---------------------------
Quarters
---------------------------
01 Jul 2018 - 30 Sep 2018
01 Apr 2018 - 30 Jun 2018
---------------------------
If the
Date = '2019-01-24' -- Where this date is under fourth quarter
Expected result:
---------------------------
Quarters
---------------------------
01 Oct 2018 - 30 Dec 2018
01 Jul 2018 - 30 Sep 2018
01 Apr 2018 - 30 Jun 2018
---------------------------
The query that I have tried:
DECLARE #dt DATETIME = '2019-01-24 18:15:59.517'
DECLARE #FirstDayOfQuarter DATETIME
DECLARE #LastDayOfQuarter DATETIME
SET #FirstDayOfQuarter = (SELECT Dateadd(qq, Datediff(qq, 0, #dt) - 1, 0))
SET #LastDayOfQuarter = (SELECT Dateadd(dd, -1, Dateadd(qq, Datediff(qq, 0, #dt)
, 0)))
DECLARE #year INT
SET #year = Datepart(year, #dt)
DECLARE #currQ NVARCHAR(max)
SET #currQ = (SELECT CONVERT(VARCHAR(20), #FirstDayOfQuarter, 106)
+ Space(1) + '-' + Space(1)
+ CONVERT(VARCHAR(20), #LastDayOfQuarter, 106))
SELECT CONVERT(NVARCHAR(20), Dateadd(m, 3*number, CONVERT(DATE, CONVERT(VARCHAR(
5),
#year)+'-1-1')), 106)
+ Space(1) + '-' + Space(1)
+ CONVERT(NVARCHAR(20), Dateadd(d, -1, Dateadd(m, 3*number+3, CONVERT(
DATE,
CONVERT(VARCHAR(5), #year)+'-1-1'))), 106) AS Quarter,
number,
CASE
WHEN #dt BETWEEN Dateadd(m, 3 * number, CONVERT(DATE, CONVERT(VARCHAR(5
),
#year) +
'-1-1')) AND
Dateadd(d, -1, Dateadd(m, 3 * number + 3,
CONVERT(DATE, CONVERT(VARCHAR(5)
,
#year
) + '-1-1'))) THEN 1
ELSE 0
END AS isCurrentQuarter
INTO #allquarters
FROM master..spt_values
WHERE type = 'p'
AND number BETWEEN 1 AND 4
SELECT TOP 1 number,
CASE
WHEN #dt BETWEEN Dateadd(m, 3 * number,
CONVERT(DATE, CONVERT(VARCHAR(5),
#year) +
'-1-1')) AND
Dateadd(d, -1, Dateadd(m, 3 * number + 3,
CONVERT(DATE, CONVERT(
VARCHAR(5),
#year
) + '-1-1'))) THEN 1
ELSE 0
END AS isCurrentQuarter
INTO #currentquarter
FROM master..spt_values
WHERE type = 'p'
AND number BETWEEN 1 AND 4
ORDER BY iscurrentquarter DESC,
number ASC
SELECT quarter
FROM #allquarters
WHERE number < (SELECT number
FROM #currentquarter)
ORDER BY number DESC
DROP TABLE #allquarters
DROP TABLE #currentquarter
It is working for GETDATE() but when I put the date as 2019-01-24 18:15:59.517 then it gives me empty result
EDIT:
If the
Date = '2019-05-24' -- Where this date is under first quarter of next year
Expected result:
---------------------------
Quarters
---------------------------
01 Jan 2019 - 30 March 2019
01 Oct 2018 - 30 Dec 2018
01 Jul 2018 - 30 Sep 2018
01 Apr 2018 - 30 Jun 2018
---------------------------
If the
Date = '2018-05-24' -- Where this date is under the first quarter of current year
Expected result:
---------------------------
Quarters
---------------------------
01 Jan 2018 - 30 March 2018
01 Oct 2017 - 30 Dec 2017
01 Jul 2017 - 30 Sep 2017
01 Apr 2017 - 30 Jun 2017
---------------------------

Answer 1

I believe this does what you want:
with dte as (
select cast('2019-07-24' as date) as dte
)
select dte,
(convert(varchar(255), dateadd(month, v.n, datefromparts(year(dte), ((month(dte) - 1) / 3) * 3 + 1, 1)), 106) + ' - ' +
convert(varchar(255), dateadd(day, -1, dateadd(month, v.n + 3, datefromparts(year(dte), ((month(dte) - 1) / 3) * 3 + 1, 1))), 106)
) as string
from dte cross apply
(values (0), (-3), (-6), (-9)) v(n)
where month(dte) < 4 or month(dte) >= 13 + v.n
order by v.n;
Here is a db<>fiddle.

Answer 2

Use the formula (n + 5) % 12 + 3 to convert month numbers 1, 2, ..., 12 to 9, 10, ..., 14, 3, ..., 8 which is the number of months you need to subtract from a given date. In SQL Server 2008 you would translate it as:
DATEADD(MONTH, DATEDIFF(MONTH, 0, inputdate) - ((MONTH(inputdate) + 5) % 12 + 3), 0)
The converts 2018-04-xx to 2017-04-01 and 2018-07-xx to 2018-04-01. Adding 3, 6 and 9 months is trivial.
DB Fiddle