How to get the last sunday of the year using TSQL? - sql

Question

I need to check if a given day is the last sunday of any year, if yes the return 1 using TSQL only.
I do not have much idea about TSQL.

Answer 1

SQL Server has a problem with weekdays, because they can be affected by internationalization settings. Assuming the defaults, you can do:
select dateadd(day,
1 - datepart(weekday, datefromparts(#year, 12, 31)),
datefromparts(#year, 12, 31)
)
Otherwise, you'll need to do a case expression to turn the day of the week into a number.
In an older version of SQL Server, you could do:
select dateadd(day,
1 - datepart(weekday, cast(#year + '0101' as date)),
cast(#year + '0101' as date)
)

Answer 2

I haven't worked with tsql specifically but if my sql knowledge and googling is good enough then something like this should do the trick:
... WHERE DATEPART(dw, date) = 7 and DATEDIFF (d, date, DATEFROMPARTS (DATEPART(yyyy, date), 12, 31)) <= 6
Basically we check if that day is Sunday at first and then if it's less than week away from last day of the year

Answer 3

Using Mr. Gordon's query, following IIF() returns 1 if given day is last Sunday of the year, returns 0 if it is not.
Using 2018 as year and 2018-12-30 as given date. You can replace values with variables.
select IIF( DATEDIFF(DAY,'2018-12-30',
DATEADD(day,
1 - datepart(weekday, datefromparts(2018, 12, 31)),
datefromparts(2018, 12, 31)
)) = 0, 1, 0)

Answer 4

You can use this function
Function Code :
create FUNCTION CheckIsSaturday
(
#date DATETIME
)
RETURNS int
AS
BEGIN
-- Declare the return variable here
DECLARE #result INT
DECLARE #DayOfWeek NVARCHAR(22)
DECLARE #LastDayOfYear DATETIME
select #LastDayOfYear=DATEADD(yy, DATEDIFF(yy, 0, #date) + 1, -1)
SELECT #DayOfWeek=DATENAME(dw, #date)
IF(#DayOfWeek='Saturday' AND DATEDIFF(dd,#date,#LastDayOfYear)<7)
RETURN 1;
RETURN 0;
END
GO
function Usage:
SELECT dbo.CheckIsSaturday('2017-12-23')

Answer 5

This becomes quite trivial if you have a Calendar Table
DECLARE #CheckDate DATE = '20181230'
;WITH cteGetDates AS
(
SELECT
[Date], WeekDayName, WeekOfMonth, [MonthName], [Year]
,LastDOWInMonth = ROW_NUMBER() OVER
(
PARTITION BY FirstDayOfMonth, [Weekday]
ORDER BY [Date] DESC
)
FROM
dbo.DateDimension
)
SELECT * FROM cteGetDates D
WHERE D.LastDOWInMonth = 1 AND D.WeekDayName = 'Sunday' and D.MonthName = 'December' AND D.[Date] = #CheckDate

Answer 6

You can also use this one to get every last day of the year:
;WITH getlastdaysofyear ( LastDay, DayCnt ) AS (
SELECT DATEADD(dd, -DAY(DATEADD(mm, 1, DATEADD(yy, DATEDIFF(yy, 0, GETDATE()) + 1, -1))),
DATEADD(mm, 1, DATEADD(yy, DATEDIFF(yy, 0, GETDATE()) + 1, -1))),
0 AS DayCnt
UNION ALL
SELECT LastDay,
DayCnt + 1
FROM getlastdaysofyear
)
SELECT *
FROM ( SELECT TOP 7 DATEADD(DD, -DayCnt, LastDay) LastDate,
'Last ' + DATENAME(Weekday,DATEADD(DD, -DayCnt, LastDay)) AS DayStatus
FROM getlastdaysofyear ) T
ORDER BY DATEPART(Weekday, LastDate)
Hope you like it :)