Explain This Query - sql

Could anyone explain this query?
SELECT CASE
WHEN DATENAME(WEEKDAY, dateadd(mm, DATEDIFF(MM, 0, getdate()), 0)) = 'Saturday'
THEN
REPLACE('RXRatingsTrialV3DailyChange' + CONVERT(VARCHAR(10), DATEADD(mm,DATEDIFF(mm,0,GETDATE()),0)+2,111),'/','')
WHEN DATENAME(WEEKDAY, dateadd(mm, DATEDIFF(MM, 0, getdate()), 0)) = 'Sunday'
THEN
REPLACE('RXRatingsTrialV3DailyChange' + CONVERT(VARCHAR(10), DATEADD(mm,DATEDIFF(mm,0,GETDATE()),0)+1,111),'/','')
ELSE
REPLACE('RXRatingsTrialV3DailyChange' + CONVERT(VARCHAR(10), DATEADD(mm,DATEDIFF(mm,0,GETDATE()),0),111),'/','')
END
AS RXRatingsTrialV3DailyChange
The result is RXRatingsTrialV3DailyChange20150501. What I really do not understand is what part of the query is writing the date, '20150501'?
Thanks

The DATEADD with the ,0) is doing this.
SELECT CASE
WHEN DATENAME(WEEKDAY, dateadd(mm, DATEDIFF(MM, 0, getdate()), 0)) = 'Saturday'
THEN
REPLACE('RXRatingsTrialV3DailyChange' + CONVERT(VARCHAR(10), DATEADD(mm,DATEDIFF(mm,0,GETDATE()),0)+2,111),'/','')
WHEN DATENAME(WEEKDAY, dateadd(mm, DATEDIFF(MM, 0, getdate()), 0)) = 'Sunday'
THEN
REPLACE('RXRatingsTrialV3DailyChange' + CONVERT(VARCHAR(10), DATEADD(mm,DATEDIFF(mm,0,GETDATE()),0)+1,111),'/','')
ELSE
REPLACE('RXRatingsTrialV3DailyChange' + CONVERT(VARCHAR(10), DATEADD(mm,DATEDIFF(mm,0,GETDATE()),0),111),'/','')
END
AS RXRatingsTrialV3DailyChange,
getdate()m,
DATEDIFF(mm,0,GETDATE()),
DATEADD(mm,DATEDIFF(mm,0,GETDATE()),0)

Related

Subtracting one month from a date but making sure it is the first business day of that month

I need to subtract one month from a date called ArchiveDate but I want the first business day of that month. For example if my ArchiveDate is 9/2/2018 I would like to have 8/1/2019.
This is what I have:
DECLARE #ArchiveDate date = '9/2/2019'
SELECT ArchiveDate = DATEADD(day,
CASE WHEN
DATEPART(weekday, DATEADD(MONTH, -1, #ArchiveDate)) = 1
THEN 1
WHEN DATEPART(weekday, DATEADD(MONTH, -1, #ArchiveDate)) = 7 THEN 2
ELSE 0
END
, DATEADD(MONTH, -1, #ArchiveDate))
What I get from this is 8/2/2019 but as you can see I want 8/1/2019.
SELECT
CASE
WHEN DATENAME(WEEKDAY, DATEADD(mm, DATEDIFF(mm, 0, #ArchiveDate) - 1, 0)) = 'Saturday'
THEN DATEADD(mm, DATEDIFF(mm, 0, #ArchiveDate) - 1, 0) + 2
WHEN DATENAME(WEEKDAY, DATEADD(mm, DATEDIFF(mm, 0, #ArchiveDate) - 1, 0)) = 'Sunday'
THEN DATEADD(mm, DATEDIFF(mm, 0, #ArchiveDate) - 1, 0) + 1
ELSE
DATEADD(mm, DATEDIFF(mm, 0, #ArchiveDate) - 1, 0)
END
This will return the first BUSINESS DAY of the previous month.
you can use eomonth along with your logic to get first day of previous month as below:
DECLARE #ArchiveDate date = '9/2/2019'
select dateadd(day, 1, eomonth(dateadd(month, -2, #ArchiveDate)));
You can use EOMONTH with DATEADD():
SELECT DATEADD(DAY, 1, EOMONTH(#ArchiveDate, -2)) AS ArchiveDate

Select the first weekday of the next Month

I am trying to modify someone else's code I found here to find the first weekday of next month (Link):
SELECT CASE
WHEN DATENAME(WEEKDAY, dateadd(mm, DATEDIFF(MM, 0, getdate()), 0)) = 'Saturday'
THEN dateadd(mm, DATEDIFF(MM, 0, getdate()), 0) + 2
WHEN DATENAME(WEEKDAY, dateadd(mm, DATEDIFF(MM, 0, getdate()), 0)) = 'Sunday'
THEN dateadd(mm, DATEDIFF(MM, 0, getdate()), 0) + 1
ELSE dateadd(mm, DATEDIFF(MM, 0, getdate()), 0)
END
Here is what I have come up with (which doesn't work):
select CASE
WHEN DATENAME(WEEKDAY, eomonth(dateadd(mm, DATEDIFF(MM, 0, getdate()),1), 0 )) = 'Saturday'
THEN eomonth(dateadd(mm, DATEDIFF(MM, 0, getdate()), 0),1) + 2
WHEN DATENAME(WEEKDAY, eomonth(dateadd(mm, DATEDIFF(MM, 0, getdate()),1), 0)) = 'Sunday'
THEN eomonth(dateadd(mm, DATEDIFF(MM, 0, getdate()), 0),1) + 1
ELSE eomonth(dateadd(mm, DATEDIFF(MM, 0, getdate()), 1),1)
end
Thanks for the help!
Your query implementation looks like for SQL server. You may use DATEFROMPARTS or EOMONTH function to get first day of next month, then use DATENAME in CASE expression to decide the first weekday like below (SQL Server only).
-- get first day of next month using DATEFROMPARTS
Declare #NextMonthFirstDate datetime = DATEFROMPARTS(YEAR(GETDATE()),MONTH(GETDATE())+1,1)
-- then use CASE expression
Select CASE WHEN DATENAME(WEEKDAY, #NextMonthFirstDate) = 'Sunday'
THEN #NextMonthFirstDate + 1
WHEN DATENAME(WEEKDAY, #NextMonthFirstDate) = 'Saturday'
THEN #NextMonthFirstDate + 2
ELSE #NextMonthFirstDate END as FirstWeekDayOfnextMonth

How to return just the yyyy-mm-dd from the following SQL queries [duplicate]

This question already has answers here:
How to get a date in YYYY-MM-DD format from a TSQL datetime field?
(25 answers)
Closed 4 years ago.
Below are the queries I created. Query #1 returns 2018-07-06 00:00:00.000 and query #2 returns 2018-07-31 23:59:59.997.
I can't figure out how to modify the queries so that they'll return the result in the yyyy-mm-dd format. Please advice.
Query #1 - get fifth business day of the month
SELECT
FifthWeekDay = DATEADD(dd, CASE
WHEN DATEDIFF(dd, -1, ca.FirstOfMonth) % 7 > 1 -- -1 is a Sunday
THEN 7
ELSE 6 - DATEDIFF(dd, -1, ca.FirstOfMonth) % 7 -- -1 is a Sunday
END, ca.FirstOfMonth - 1)
FROM
(SELECT
DATEADD(mm, (SELECT DATEPART(YEAR, GETDATE())) * 12 - 22801 +
(SELECT DATEPART(M, GETDATE())), 0)) ca(FirstOfMonth)
Query #2 - get last business day of the month
SELECT
DATEADD(ms, -3, DATEADD(mm, DATEDIFF(mm, 0, GETDATE()) + 1, 0))
- CASE DATENAME(dw, DATEADD(ms, -3, DATEADD(mm, DATEDIFF(mm, 0, GETDATE()) + 1, 0)))
WHEN 'SUNDAY' THEN 2
WHEN 'SATURDAY' THEN 1
ELSE 0
END AS LastBusinessCurrentMonth
You can subquery the results you already have and add a cast( as date):
SELECT CAST(LastBusinessCurrentMonth AS DATE) AS LastBusinessCurrentMonth FROM(
SELECT
DATEADD(ms, -3, DATEADD(mm, DATEDIFF(mm, 0, GETDATE()) + 1, 0))
- CASE DATENAME(dw, DATEADD(ms, -3, DATEADD(mm, DATEDIFF(mm, 0, GETDATE()) + 1, 0)))
WHEN 'SUNDAY' THEN 2
WHEN 'SATURDAY' THEN 1
ELSE 0
END AS LastBusinessCurrentMonth) AS X
SELECT CAST(FIFTHWEEKDAY AS DATE) AS FIFTHWEEKDAY FROM(
SELECT
FifthWeekDay = DATEADD(dd, CASE
WHEN DATEDIFF(dd, -1, ca.FirstOfMonth) % 7 > 1 -- -1 is a Sunday
THEN 7
ELSE 6 - DATEDIFF(dd, -1, ca.FirstOfMonth) % 7 -- -1 is a Sunday
END, ca.FirstOfMonth - 1)
FROM
(SELECT
DATEADD(mm, (SELECT DATEPART(YEAR, GETDATE())) * 12 - 22801 +
(SELECT DATEPART(M, GETDATE())), 0)) ca(FirstOfMonth)) AS X
Or you could declare a variable as Date and set the results of your queries to that variable :
DECLARE #DATEVAR DATE
SET #DATEVAR =(
SELECT
DATEADD(ms, -3, DATEADD(mm, DATEDIFF(mm, 0, GETDATE()) + 1, 0))
- CASE DATENAME(dw, DATEADD(ms, -3, DATEADD(mm, DATEDIFF(mm, 0, GETDATE()) + 1, 0)))
WHEN 'SUNDAY' THEN 2
WHEN 'SATURDAY' THEN 1
ELSE 0
END AS LastBusinessCurrentMonth)
SELECT #DATEVAR AS LastBusinessCurrentMonth
SET #DATEVAR = (SELECT
DATEADD(ms, -3, DATEADD(mm, DATEDIFF(mm, 0, GETDATE()) + 1, 0))
- CASE DATENAME(dw, DATEADD(ms, -3, DATEADD(mm, DATEDIFF(mm, 0, GETDATE()) + 1, 0)))
WHEN 'SUNDAY' THEN 2
WHEN 'SATURDAY' THEN 1
ELSE 0
END AS LastBusinessCurrentMonth)
SELECT #DATEVAR AS LastBusinessCurrentMonth

First business day of the current month - SQL Server

How could I get the first business day of the current month?
Without create a function, only select.
something like that:
SELECT CONVERT(VARCHAR(25),DATEADD(dd,-(DAY(GETDATE())-1), GETDATE()), 101)
somebody knows please?
Thanks.
A Simple case statement could do it
SELECT CASE
WHEN DATENAME(WEEKDAY, dateadd(mm, DATEDIFF(MM, 0, getdate()), 0)) = 'Saturday'
THEN dateadd(mm, DATEDIFF(MM, 0, getdate()), 0) + 2
WHEN DATENAME(WEEKDAY, dateadd(mm, DATEDIFF(MM, 0, getdate()), 0)) = 'Sunday'
THEN dateadd(mm, DATEDIFF(MM, 0, getdate()), 0) + 1
ELSE dateadd(mm, DATEDIFF(MM, 0, getdate()), 0)
END
This will literally give you what you're asking for -- the first business day in a month if we define a business day as "any day that's not a Saturday or a Sunday". But this is is a very narrow definition of "business day" that is not appropriate when taking into account holidays and cultural differences, so it generalizes poorly. The typical solution for this problem is to create a table that actually holds the working days (which is generated somewhere just before he year, or calculated in advance if that's feasible), and simply look it up in that.
SELECT DATEADD(DAY,
CASE
(DATEPART(WEEKDAY, DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()), 0)) + ##DATEFIRST - 1) % 7
WHEN 6 THEN 2
WHEN 7 THEN 1
ELSE 0
END,
DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()), 0)
)
This solution uses ##DATEFIRST to avoid any language issues -- using DATEPART(WEEKDAY, ...) on its own or DATENAME() only works if we assume a specific region.
If you have more flexibility in your SELECT statement, you might be able to use something like this:
;With Daterange As
(
Select DateAdd(Month, DateDiff(Month, 0, GetDate()), 0) As Date Union All
Select DateAdd(Day, 1, Date) As Date
From DateRange
Where Date < DateAdd(Day, 6, DateAdd(Month, DateDiff(Month, 0, GetDate()), 0))
)
Select Convert(Date, Min(Date)) FirstBusinessDay
From Daterange
Where DatePart(WeekDay, Date) Not In (7, 1)
Try this.
SELECT CASE
WHEN Datename(dw, Dateadd(dd, -Datepart(dd, Getdate()) + 1, Getdate())) = 'Saturday' THEN Dateadd(dd, -Datepart(dd, Getdate()) + 3, Getdate())
WHEN Datename(dw, Dateadd(dd, -Datepart(dd, Getdate()) + 1, Getdate())) = 'Sunday' THEN Dateadd(dd, -Datepart(dd, Getdate()) + 2, Getdate())
ELSE Dateadd(dd, -Datepart(dd, Getdate()) + 1, Getdate())
END
Explanation :
Find the first day of the month.
Dateadd(dd, -Datepart(dd, Getdate()) + 1, Getdate())
Then check the day of the previous date by using Datename function.
Datename(dw, Dateadd(dd, -Datepart(dd, Getdate()) + 1, Getdate()))
If the Datename is Saturday the add 2 days to the first day of the month . if it is sunday then add 1 day to the first day of the month else get the first day of the month

SQL Server correct way to account for the weekend

I have a few sql statements where I manually enter the date everyday then execute.
I would like to automate the date part. But weekends are giving me trouble. I use excel to run the reports as it is then saved and another member of staff does a mailshot.
This is my test example:
if (datename(dw, getdate()) = 'Friday') BEGIN
select convert(varchar, dateadd(day, 7, DATEADD(dd, 0, DATEDIFF(dd, 0,getdate()))), 103)
+ ',' + convert(varchar, dateadd(day, 9, DATEADD(dd, 0, DATEDIFF(dd, 0,getdate()))), 103) AS [Date] END
ELSE BEGIN select convert(varchar, dateadd(day, 7, DATEADD(dd, 0, DATEDIFF(dd, 0,getdate()))), 103) as [Date] END;
But how would I put this into a sql where statement?
for example
select * from table where (date = )
where Date equals 7 days in advance unless It's Friday when we have to account for the weekend so we want 7,8 and 9 days in advance?
select * from table where date = (case
when datename(dw, getdate()) = 'Friday' then
convert(varchar, dateadd(day, 7, DATEADD(dd, 0, DATEDIFF(dd, 0,getdate()))), 103)
+ ',' + convert(varchar, dateadd(day, 9, DATEADD(dd, 0, DATEDIFF(dd, 0,getdate()))), 103)
else
convert(varchar, dateadd(day, 7, DATEADD(dd, 0, DATEDIFF(dd, 0,getdate()))), 103)
end)