FiscalYear Calendar in SQL Server - sql-server

Question

I have a requirement to create a Financial year Calendar with
start date = 2019-03-31 and end_date = 2020-03-28
declare #startdate date = '2019-03-30'
declare #enddate date = '2020-03-28'
declare #dates table (date date, MonthNo int)
while #startdate < #enddate
BEGIN
set #startdate = dateadd(dd,1,#startdate)
insert #dates (date)
select #startdate
END
select * from #dates
I will need to populate month number column
MonthNumber : In this case, It can not be obtained through typical query using
DATEPART(MONTH, [date])
Requirement : Month number should be starting at 1 and should be assigned as shown below
NoOfDays trading_month
28 1
28 2
35 3
28 4
28 5
35 6
28 7
28 8
35 9
28 10
28 11
35 12
Ex: Trading month = 1 is between 2019-03-31 and 2019-04-28 and next 28 days = month 2 and next 35 days month = 3 etc..
ps: I do not want to use case statement 12 times to populate month number, is there any alternate way to achieve this
can achieve this way
select *, case when ROW_NUMBER() over (order by date) between 1 and 28 then 1
when ROW_NUMBER() over (order by date) between 29 and 28+28 then 2
when ROW_NUMBER() over (order by date) between 28+28+1 and 28+29+35 then 3
----so on
end MonthNo
from #dates

Answer 1

Here is one option.
Example
Declare #Date1 date = '2019-03-31'
Select [Date]=DateAdd(DAY,Row_Number() over (Order by M,D)-1,#Date1)
,[Year]=DatePart(YEAR,#Date1)
,[Month]=M
From (
Select *
From (Select Top (28) D=Row_Number() Over (Order By (Select Null)) From master..spt_values n1 ) A
Cross Join (Values (1),(2),(4),(5),(7),(8),(10),(11)) B(M)
Union All
Select *
From ( Select Top (35) D=Row_Number() Over (Order By (Select Null)) From master..spt_values n1 ) A
Cross Join (Values (3),(6),(9),(12)) B(M)
) A
Order by 1,2
Returns
Date Year Month
2019-03-31 2019 1
2019-04-01 2019 1
2019-04-02 2019 1
2019-04-03 2019 1
2019-04-04 2019 1
2019-04-05 2019 1
2019-04-06 2019 1
2019-04-07 2019 1
2019-04-08 2019 1
2019-04-09 2019 1
...
2020-03-21 2019 12
2020-03-22 2019 12
2020-03-23 2019 12
2020-03-24 2019 12
2020-03-25 2019 12
2020-03-26 2019 12
2020-03-27 2019 12
2020-03-28 2019 12

Answer 2

Lucky you ... Download and execute the code in my article SQL Server Calendar Table, then download and modify the code in SQL Server Calendar Table: Fiscal Years to fit your definition of a fiscal year and execute that.
I once had a client that ran on 'Crop year' where their fiscal years started the last week of May, and the only way to pull that off was to create a wompload of T-SQL to populate a Calendar table. Once that was done for any given dataset all I had to do was JOIN on the date column and then I could get all the fiscal-related column values I wanted without having to recalculate them every time.
{edit: Here's the relevant code that creates the 4-4-5 from the above Fiscal Weeks article}
USE calendar
GO
/*
Calendar table: Populate the six fiscal_ columns
2015-09-16
*/
Declare #dtYearStart date, #dtStart date, #dtEnd date, #dt date
Declare #fiscal_month tinyint = 1, #fiscal_year smallint , #fiscal_week_in_month tinyint, #fiscal_week_in_year tinyint, #fiscal_day_in_week tinyint, #fiscal_day_in_month tinyint
Declare #counter int = 1, #counter_year int = 1, #counter_month int = 1, #counter_week int = 1, #counter_day int = 1
-- Run this for 19 years from May 2000 to May 2020
WHILE #counter_year <= 19
begin
-- Per the article image, the last day of the year is the last Sunday in May.
SELECT #dtYearStart = MAX(PKDate), #dtEnd = MAX(PKDate)
FROM days
WHERE continuous_year = #counter_year AND calendar_month = 5 AND calendar_day_in_week = 1
-- YEARS and MONTHS
-- Set the year
SELECT #fiscal_year = YEAR(#dtYearStart) + 1, #fiscal_month = 1
SET #counter = 1
WHILE #counter <= 12
begin
SELECT #dtStart = DATEADD(day, 1, #dtEnd)
SELECT #dtEnd = DATEADD(day, CASE WHEN #fiscal_month IN (1, 4, 7, 10) THEN 34 ELSE 27 END, #dtStart)
UPDATE days
SET fiscal_year = #fiscal_year, fiscal_month = #fiscal_month
FROM days
WHERE PKDate >= #dtStart AND PKDate <= #dtEnd
;WITH ro AS (SELECT PKDate, RANK() OVER (ORDER BY PKDate) as row_order FROM days WHERE fiscal_year = #fiscal_year AND fiscal_month = #fiscal_month)
UPDATE days
SET fiscal_day_in_month = row_order
FROM days
JOIN ro ON days.PKDate = ro.PKDate
-- TESTING ONLY, comment the below line out in production
-- SELECT 'Year and Month' as label, PKDate, fiscal_year, fiscal_month, fiscal_day_in_month FROM days WHERE PKDate >= #dtStart AND PKDate <= #dtEnd
SELECT #counter = #counter + 1, #fiscal_month = #fiscal_month + 1
end
-- WEEKS
SELECT #counter = 1, #counter_week = 1, #dtEnd = #dtYearStart
WHILE #counter <= 52
begin
SELECT #dtStart = DATEADD(day, 1, #dtEnd)
SELECT #dtEnd = DATEADD(day, 6, #dtStart)
UPDATE days
SET fiscal_week_in_month = #counter_week, fiscal_week_in_year = #counter
FROM days
WHERE PKDate >= #dtStart AND PKDate <= #dtEnd
-- TESTING ONLY, comment the below line out in production
-- SELECT 'Week' as label, PKDate, fiscal_week_in_year, fiscal_week_in_month FROM days WHERE PKDate >= #dtStart AND PKDate <= #dtEnd
SELECT #counter = #counter + 1
-- Get the fiscal month of the row to determine if the month has 4 or 5 weeks.
SELECT #fiscal_month = fiscal_month FROM days WHERE PKDate = #dtStart
SELECT #counter_week = CASE
WHEN #fiscal_month IN (1, 4, 7, 10) AND #counter_week = 5 THEN 1
WHEN #fiscal_month IN (1, 4, 7, 10) AND #counter_week < 5 THEN #counter_week + 1
WHEN #fiscal_month NOT IN (1, 4, 7, 10) AND #counter_week = 4 THEN 1
WHEN #fiscal_month NOT IN (1, 4, 7, 10) AND #counter_week < 4 THEN #counter_week + 1 END
end
-- DAYS
;WITH ro AS (SELECT PKDate, RANK() OVER (ORDER BY PKDate) as row_order FROM days WHERE fiscal_year = #fiscal_year)
UPDATE days
SET fiscal_day_in_year = row_order
FROM days
JOIN ro ON days.PKDate = ro.PKDate
SELECT #counter_year = #counter_year + 1
end
Good luck.
Jim

Answer 3

I was able to get the expected results with the following query. The only addition to the original table was an identity column. Using most of your original code:
declare #startdate date = '2019-03-30'
declare #enddate date = '2020-03-28'
declare #dates table (pkindex int IDENTITY(1,1), [date] date, MonthNo tinyint)
while #startdate < #enddate
BEGIN
set #startdate = dateadd(dd,1,#startdate)
insert #dates ([date])
select #startdate
END
DECLARE #requirments TABLE (NoOfDays tinyint, trading_month tinyint)
INSERT INTO #requirments VALUES
(28, 1), (28, 2), (35, 3), (28, 4), (28, 5), (35, 6), (28, 7), (28, 8), (35, 9)
,(28, 10), (28, 11), (35, 12)
UPDATE #dates
SET MonthNo =
(SELECT MIN(R.trading_month)
FROM #requirments R
WHERE pkindex <
(SELECT SUM(R2.NoOfDays)
FROM #requirments R2
WHERE R2.trading_month < R.trading_month + 1
) + 1
)
SELECT * FROM #dates

Answer 4

Not sure if I understand your goal here exactly, why 1 = 28 specifically. However it seems like your datepart idea was inline with your desired solution if you just do this I get the layout you wanted.
declare #startdate date = '2019-03-30'
declare #enddate date = '2020-03-28'
declare #dates table (NoOfDays date, trading_mo int)
while #startdate < #enddate
BEGIN
set #startdate = dateadd(dd,1,#startdate)
insert #dates (NoOfDays)
select #startdate
END
select count(NoOfDays) noOfDays,
datepart(month,NoOfDays) trading_mo
from #dates
group by datepart(month,NoOfDays)
order by trading_mo