Getting last 6 months data from week column - sql-server

There is an int field say WeekNum and shows data like 202113, 202120.
And I want to get the for last 6 months.
If I subtract (weekid-26), then it will not give correct result.
Can there be a better way to get the result. Data in the current week can be anything like 202101 201952, etc.
DateAdd( month, -6) is not working here.
Sample data is:
WeekID
202110
202109
202108
202111
And the expected result is
WeekID:
201936
201935
201934
201935

You should always store dates in date or datetime fields, otherwise you run into problems such as you have
You need to divide by 100 to get the year, and modulo by 100 to get the week (unclear if it's week or isoweek)
SELECT *
FROM table1
WHERE DATEADD(week, WeekNum % 100, DATEFROMPARTS(WeekNum / 100, 1, 1)) >=
DATEADD(month, -6, GETDATE())

Related

Convert DateTimeOffset to DateTime in a where between 23:00 previous day an 07:00 Am next day for past 2 weeks

I have to make an query on a table where the datetime field is of type datetimeoffset.
The query itself is already difficult, but now working with conversions makes it even more complicated. What I want out of the table is to retrieve everything between 23:00 previous day to 07:00 the next morning for the past 2 weeks. I have tried numerous ways, but think I am just staring at a screen momentarily. Below is one of my last attempts before posting here, what am I missing here:
SELECT *
FROM Occurrences
WHERE SWITCHOFFSET(CreatedOn,'+01:00') >= DATEADD(hh,23,DATEADD(day, DATEDIFF(day, 0,
SWITCHOFFSET(CreatedOn,'+01:00') - 1), 0))
AND SWITCHOFFSET(CreatedOn,'+01:00') < DATEADD(hh,7,DATEADD(day, DATEDIFF(day, 0,
SWITCHOFFSET(CreatedOn,'+01:00')), 0))
ORDER BY CreatedOn DESC
Just note This is without the 2 weeks filter. Just wanted to see some results atleast, but get an error:
Operand type clash: datetimeoffset is incompatible with int
The CreatedOn has a entry like "2022-11-15 09:24:13.6096718 +01:00" and the type of field is a datetimeoffset(7)
This does work though in it simplest form:
SELECT TOP 1 SWITCHOFFSET(CreatedOn,'+01:00') FROM Occurrences ORDER BY CreatedOn DESC
Just check that the hour part is either above 23 or below 7, then check it occurred less than 2 weeks ago.
SELECT *
FROM Occurrences
WHERE (DATEPART(hh, SWITCHOFFSET(CreatedOn,'+00:01')) >= 23 OR DATEPART(hh, SWITCHOFFSET(CreatedOn,'+00:01')) < 7) AND (SWITCHOFFSET(CreatedOn,'+00:01') > CONVERT(datetimeoffset, DATEADD(day, -14, GETDATE()),'+00:01'))
ORDER BY CreatedOn DESC

How to find the past 4 weeks of the same weekday value starting today

I am trying to select records from today and the same day of each week for the last 4 weeks.
Today (Tuesday)
Last Tuesday
The Tuesday before that
The Tuesday before that
I need this to be tied to current date because I am going to run this query every day so I don't want to use a between or something where I manually specify the date range.
Everything I have found or tried so far has pulled the last month of data but not the last 4 weeks of the same weekday.
select *
from table
where thedatecolumn >= DATEADD(mm, -1, GETDATE())
This works but pulls everything from the last month.
If today's date is 7/10/2019 I need
Data from 7/10/2019
Data from 7/3/2019
Data from 6/26/2019
Data from 6/19/2019
Every day I will run this query, so I need it to be dynamic based on the current date.
I believe you want to look back 21 days and then filter those dates that have the same day of week:
select * from table
where thedatecolumn >= DATEADD(DAY, -21, CAST(GETDATE() AS DATE))
and DATEPART(WEEKDAY, thedatecolumn) = DATEPART(WEEKDAY, GETDATE())
You Can try using a recursive cte which starts today and repeatedly substracts 7 days - so you ensure you always land on the same weekday. Following an example:
WITH cteFromToday AS(
SELECT 0 AS WeeksBack, GETDATE() AS MyDate
UNION ALL
SELECT WeeksBack + 1 AS WeeksBack, DATEADD(d, -7, MyDate) AS MyDate
FROM cteFromToday
)
SELECT TOP 5 *
FROM cteFromToday
OPTION ( MaxRecursion 0 );
This is quite simple. Substitute CURRENT_TIMESTAMP here for any given date.
SELECT CONVERT(DATE,CURRENT_TIMESTAMP) AS Today,
DATEADD(DAY,-7,CONVERT(DATE,CURRENT_TIMESTAMP)) AS LastWeek ,
DATEADD(DAY,-14,CONVERT(DATE,CURRENT_TIMESTAMP)) AS TwoWeeksAgo,
DATEADD(DAY,-21,CONVERT(DATE,CURRENT_TIMESTAMP)) AS ThreeWeeksAgo
SO, if you want to get data for a set of ranges for one entire day with those dates:
SELECT something
WHERE
datetimecolumn >= CONVERT(DATE,CURRENT_TIMESTAMP) AND datetimecolumn < DATEADD(DAY,1, CONVERT(DATE,CURRENT_TIMESTAMP)) -- Todays range,
OR datetimecolumn >= DATEADD(DAY,-7,CONVERT(DATE,CURRENT_TIMESTAMP)) AND datetimecolumn < DATEADD(DAY,1,DATEADD(DAY,-7,CONVERT(DATE,CURRENT_TIMESTAMP)))-- LastWeek ,
OR datetimecolumn >= DATEADD(DAY,-14,CONVERT(DATE,CURRENT_TIMESTAMP)) AND datetimecolumn < DATEADD(DAY,1,DATEADD(DAY,-14,CONVERT(DATE,CURRENT_TIMESTAMP)))-- TwoWeeksAgo,
OR datetimecolumn >= DATEADD(DAY,-21,CONVERT(DATE,CURRENT_TIMESTAMP)) AND datetimecolumn < DATEADD(DAY,1, DATEADD(DAY,-21,CONVERT(DATE,CURRENT_TIMESTAMP))) -- ThreeWeeksAgo

SQL Server Parameter Date Range Issues

I am using the following query to get the difference between two dates. The date ranges are tolling 12 months interval.
CY stand for Current year while PY stands for Previous Year. The dates in Current year are used to calculate the previous year dates
When I execute my query I have the following output, where the month is 11 and day 364. But I want my months to be twelve and the day 365 or (366 for leap year).
DECLARE #CY_StartDate date =CAST(DATEADD(MONTH, DATEDIFF(MONTH, -1, GETDATE())-13, 0) AS DATE),
#CY_EndDate date =CAST(DATEADD(MONTH, DATEDIFF(MONTH, -1, GETDATE())-1, -1) AS DATE); --- Rolling 12 months
DECLARE #PY_startDate date =DATEADD(YEAR,-1,#CY_StartDate),
#PY_EndDate date =DATEADD(YEAR,-1,#CY_EndDate)
SELECT
#CY_StartDate AS CY_Start,
#CY_EndDate AS CY_End,
#PY_StartDate AS PY_Start,
#PY_EndDate AS PY_End,
DATEDIFF(year, #CY_StartDate, #CY_EndDate) AS yr,
DATEDIFF(month, #CY_StartDate, #CY_EndDate) AS month,
DATEDIFF(day, #CY_StartDate, #CY_EndDate) AS day
Current Output
CY_Start CY_End PY_Start PY_End yr month day
2017-10-01 2018-09-30 2016-10-01 2017-09-30 1 11 364
Expected output
CY_Start CY_End PY_Start PY_End yr month day
2017-10-01 2018-09-30 2016-10-01 2017-09-30 1 12 365
The values you are getting make sense. DATEDIFF counts the ticks between 2 dates, where a tick is the value of the first parameter. So, for example: DATEDIFF(MONTH, '20180101','20180228') will return 1, as only 1 tick has occured (2 - 1 = 1). Seems, here, you simply need to add 1:
DECLARE #CY_StartDate date =CAST(DATEADD(MONTH, DATEDIFF(MONTH, -1, GETDATE())-13, 0) AS DATE),
#CY_EndDate date =CAST(DATEADD(MONTH, DATEDIFF(MONTH, -1, GETDATE())-1, -1) AS DATE); --- Rolling 12 months
DECLARE #PY_startDate date =DATEADD(YEAR,-1,#CY_StartDate),
#PY_EndDate date =DATEADD(YEAR,-1,#CY_EndDate)
select
#CY_StartDate as CY_Start,
#CY_EndDate AS CY_End,
#PY_StartDate AS PY_Start,
#PY_EndDate AS PY_End,
DATEDIFF(year,#CY_StartDate,DATEADD(DAY,1,#CY_EndDate)) as yr,
DATEDIFF(month,#CY_StartDate,DATEADD(DAY,1,#CY_EndDate)) as month,
DATEDIFF(day,#CY_StartDate,DATEADD(DAY,1,#CY_EndDate)) as day
The reason I used a further DATEADD is because this makes it consistent with every expression. The value of yr was correct, however, for dates like 20170101 and 20171231, the value of yr would be 0. Hence adding 1 day the the value of #CY_EndDate makes this far more reliable, should the dates move.
Common sense. How many numbers are there between 1 and 10 including both? You might say that there are 10 - 1 = 9 which is incorrect. The correct answer is (10 - 1) + 1 = 10.
Likewise, if you have two inclusive dates e.g. 2017-10-01 and 2018-09-30 you add one to DATEDIFF(DAY, '2017-10-01', '2018-09-30') to get 365 instead of 364.
However, as suggested in the other answer, it is much better to the end date exclusive (not counted) which makes date calculations straight forward. In your example, you should add 1 day to the last date so that you have [2017-10-01, 2018-10-01) and DATEDIFF will produce desired results.

Convert number of hours to days and hours in SQL Server (NOT T-SQL)

I have a number of hours which I need to display in the format of days and hours.
This number is derived from a DATEDIFF instruction.
For numbers less than 24, I wish to display only hours - ie, 21 hours.
For larger numbers, I wish to display days and hours - ie, 3 days, 14 hours
I do not need to display any smaller unit than hours, and values should be rounded down to the preceding hour, so 1 hour and 59 minutes will be 1 hour.
I cannot use a stored procedure - this must run as a single select statement.
I am aware that I can calculate the value by using modulo, so assuming 71 hours:
select concat((71 - (71 % 24)) / 24, ' days, ', 71 % 24, ' hours')
This however is somewhat messy, and as the statement must be a single select, I will have to calculate the DATEDIFF 3 times as below.
SELECT CONCAT (
(DATEDIFF(HOUR, StartDate, EndDate) -
(DATEDIFF(HOUR, StartDate, EndDate) % 24)) / 24,
' days, ',
DATEDIFF(HOUR, StartDate, EndDate) % 24,
' hours')
FROM RecordsTable
Is it possible to either format a number of hours as days and hours directly using an inbuilt SQL command, or failing that, select (datediff(hour, StartDate, EndDate) into a variable which I can reuse in the single select?
EDIT - As suggested, the solution was to use a CTE as follows:
WITH totalhours (htotal) AS
(
SELECT
DATEDIFF(HOUR, StartDate, EndDate) AS htotal
FROM
RecordsTable
)
SELECT
CONCAT ((htotal - (htotal % 24)) / 24,
' days, ',
htotal % 24,
' hours')
FROM
RecordsTable;
Use a CTE to generate your total once, and reference that total in your select against the CTE. Or use a subquery to generate the total once and then select from the subquery to get the desired results.
The fundamental issue is you need to materialize the total once to be able to reference it; forcing the engine to materialize a value is generally done via a CTE or subquery.
You can do a lot with datetime objects and format strings or datepart. For example,
declare #n int = 105;
select format(dateadd(day, -1, dateadd(hour, #n, '1753-1-1')), 'd h');
-- 4 9
Taking the minimum datetime value (1753-01-01), adding the requisite number of hours, subtracting one day (because on the first day you want days = 0), and then formatting.
You could improve the formatting like this:
select format(dateadd(day, -1, dateadd(hour, #n, '1753-1-1')), 'd \da\y(\s), h \hour(\s)');
-- 4 day(s), 9 hour(s)
Of course this will only work up to 31 days, because then you'll be out of the month of January in 1753 and into February. If that's the case, revert to datepart. This is uglier, but will work for larger values
select
datepart(day, (dateadd(day, -1, dateadd(hour, #n, '1753-1-1')))),
datepart(hour, (dateadd(day, -1, dateadd(hour, #n, '1753-1-1'))));

Counting datediff from 2 date

I have 2 datetime fields, NEW_EMPLOYMENT_STARTDATE and NEW_EMPLOYMENT_ENDDATE
When I calculate the difference in months using datediff with these values for startdate and enddate:
NEW_EMPLOYMENT_STARTDATE = 2017-15-01
NEW_EMPLOYMENT_ENDDATE = 2018-14-01
With this query:
DATEDIFF(MONTH, NEW_EMPLOYMENT_STARTDATE, NEW_EMPLOYMENT_ENDDATE)
It returns 12 months, but when I have values like this:
NEW_EMPLOYMENT_STARTDATE = 2017-01-01
NEW_EMPLOYMENT_ENDDATE = 2017-31-12
It returns 11 months.
How can I get 12 months? I am using this query:
DATEDIFF(MONTH, NEW_EMPLOYMENT_STARTDATE, NEW_EMPLOYMENT_ENDDATE)-
CASE
WHEN DATEPART(DAY, NEW_EMPLOYMENT_ENDDATE) > DATEPART(DAY, NEW_EMPLOYMENT_STARTDATE)
THEN 0
ELSE 0 END AS MONTH_DIFF
It still returns 11 months.
EDIT:
According to my case, the value of the end date always less 1 day from start date, so i make a trick to check condition with case when like this:
CASE
WHEN DATEPART(DAY, NEW_EMPLOYMENT_ENDDATE) > DATEPART(DAY, NEW_EMPLOYMENT_STARTDATE)
THEN DATEDIFF(MONTH, NEW_EMPLOYMENT_STARTDATE, NEW_EMPLOYMENT_ENDDATE)+1
ELSE DATEDIFF(MONTH, NEW_EMPLOYMENT_STARTDATE, NEW_EMPLOYMENT_ENDDATE)
END AS DATEDIF
i add + 1 value to the end date so i ta can be round to next month, give feedback from my solution sir thanks
You're expectations are incorrect. When you do a DATEDIFF using MONTH, it does not consider the day portion of the dates. Consider that it is simply considering the difference in the month numbers only, regardless of the day specified.
This query:
SELECT DATEDIFF(MONTH, '20170101', '20171231') MonthsDiff
Is equivalent to this:
SELECT DATEPART(MONTH, '20171231') - DATEPART(MONTH, '20170101') MonthsDiff
The documentation for DATEDIFF states:
DATEDIFF ( datepart , startdate , enddate )
The first option is DATEPART:
datepart
Is the part of startdate and enddate that specifies the type of boundary crossed.
If you want something closer to what you expect, you can do a simple calculation based on performing the DATEDIFF in days, the dividing it by the approximate number of days in a month.
SELECT DATEDIFF(DAY, '20170101', '20171231') / ( 365 / 12 ) MonthsDiff
This will round the output to the closest month number, it all depends on how accurate you want to be. If you want months as a decimal for greater accuracy then run the below:
SELECT DATEDIFF(DAY, '20170101', '20171220') / ( 365.00 / 12 ) MonthsDiff
Note: This does not take into account leap years, for larger date ranges that might include leap years, which will make a minor difference to the accuracy.
datediff() does something very particular. It counts the number of "boundaries" between two date/time values. In your case, there are eleven boundaries -- one for each month in the year before December.
This behavior is not necessarily intuitive. If you add one day to each of your dates:
NEW_EMPLOYMENT_STARTDATE = '2017-01-02' (YYYY-MM-DD is standard format)
NEW_EMPLOYMENT_ENDDATE = '2018-01-01'
Then you will have 12 months.
If you want to round up, you can play with the dates. One method would be to normalize the first value to the beginning of the month and then add 15 days to the second value:
DATEDIFF(MONTH,
DATEADD(DAY, 1 - DAY(NEW_EMPLOYMENT_STARTDATE), NEW_EMPLOYMENT_STARTDATE)
DATEADD(DAY, 15 + 1 - DAY(NEW_EMPLOYMENT_STARTDATE), NEW_EMPLOYMENT_ENDDATE)
)
This would happen to work for the two examples you give.
Please use this select to achieve your desired result. You can use table columns instead of variables:
declare #new_employment_startdate datetime = convert (datetime, '2017-01-01', 121);
declare #new_employment_enddate datetime = convert (datetime, '2018-01-14', 121);
select
datediff(month, #new_employment_startdate, #new_employment_enddate)
+ case when
datediff(month, dateadd(ms, -3, dateadd(dd, datediff(dd, 0, #new_employment_startdate), 0)), #new_employment_startdate) = 1
and datediff(month,#new_employment_enddate , dateadd(dd, datediff(dd, 0, #new_employment_enddate) + 1, 0)) = 1
then 1
else 0
end;
Some explanations:
I check or start date is first month day AND end date is last month day. At this case I add +1 to standard datediff by month.
You can better understand my used datetime manipulations by using these example queries: https://gist.github.com/runnerlt/60636b029ab47845fdfd8924ed482e61
You need to add 1 more day in your End Date.
DATEDIFF(MONTH, NEW_EMPLOYMENT_STARTDATE, DATEADD(DD,1,NEW_EMPLOYMENT_ENDDATE))
You could match the output with MS Excel.

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