Last Wednesday of every month - sql

Question

I need to work out the last Wednesday for each month in a range of dates.
I have the code for calculating the last Wednesday, but my cte doesn't seem to step through the months correctly.
Current code:
declare #S_Date date
declare #E_Date date
set #S_Date='2016-01-31' --eomonth of first month
set #E_Date='2016-06-15' --ides of last month ( can actually be any day that is
--not equal to or after the last Wednesday of the month)
;with LW(D_Date) as
(
select dateadd(dd,datediff(dd,0,#S_Date)/7*7+2,0)
union all
select dateadd(dd,datediff(dd,0,eomonth(D_Date,1))/7*7+2,0)
from LW
where D_date<#E_Date
)
select d_date
from LW
changing the eomonth to
select dateadd(dd,datediff(dd,0,dateadd(mm,1,D_Date))/7*7+2,0)
doesn't seem to work either
Expected results:
2016-01-27
2016-02-24
2016-03-30
2016-04-27
2016-05-25
2016-06-29

Answer 1

Here's a way to do it with EOMONTH() and DATEFROMPARTS():
declare #S_Date date
declare #E_Date date
set #S_Date='2016-01-31' --eomonth of first month
set #E_Date='2016-06-15' --ides of last month ( can actually be any day that is
--not equal to or after the last Wednesday of the month)
;With Date (Date) As
(
Select DateFromParts(Year(#S_Date), Month(#S_Date), 1) Union All
Select DateAdd(Day, 1, Date)
From Date
Where Date < EOMonth(#E_Date)
)
Select Max(Date) As LastWednesday
From Date
Where DatePart(WeekDay, Date) = 4
Group By Year(Date), Month(Date)
Option (MaxRecursion 0)
Output
LastWednesday
2016-01-27
2016-02-24
2016-03-30
2016-04-27
2016-05-25
2016-06-29

Answer 2

Here a slightly different approach without the partitioning... result should be the same:
declare #S_Date date
declare #E_Date date
set #S_Date='2016-01-31' --eomonth of first month
set #E_Date='2016-06-15' --ides of last month ( can actually be any day that is
--not equal to or after the last Wednesday of the month)
;With Date (Date, WD) As
(
Select DateFromParts(Year(#S_Date), Month(#S_Date), 1), DatePart(WeekDay, DateFromParts(Year(#S_Date), Month(#S_Date), 1)) AS wd
Union All
Select DateAdd(Day, 1, Date), DatePart(WeekDay, DateAdd(Day, 1, Date)) AS wd
From Date
Where Date < EOMonth(#E_Date)
)
Select Max(Date) As LastWednesday
From Date
Where wd = 4
group by MONTH(Date)
Option (MaxRecursion 0)

Answer 3

You need a calendar table ..I have a calendar table and below screenshot shows you how simple it is check or get last wednesday of each month..
query used:
select * from dbo.calendar where year='2013' and wkdname='Wednesday'
and last=1
Output of above query which you can modify as per your requirement:

Answer 4

This is rather straightforward solution with eomonth.
declare #s_date date='2016-01-01',#e_date date='2016-12-31' --date range
;with eom_tbl as (--CTE
--anchor from start date
select EOMONTH(#s_date,0) eom,datepart(weekday,EOMONTH(#s_date,0)) dw
union all
--recursive query
select EOMONTH(eom,1) eom,datepart(weekday,EOMONTH(eom,1)) dw
from eom_tbl where eom<#e_date
)
select eom,dw,
--calculate last Wednesday (4)
case when dw<4 then dateadd(dd,-3-dw,eom)
else dateadd(dd,4-dw,eom) end lastWed,
--extra check
datepart(dw,case when dw<4 then dateadd(dd,-3-dw,eom)
else dateadd(dd,4-dw,eom) end ) ddw
from eom_tbl