I have a column with values like '3rd-Wednesday', '2nd-Tuesday', 'Every-Thursday'.
I'd like to create a column that reads those strings, and determines if that date has already come this month, and if it has, then return that date of next month. If it has not passed yet for this month, then it would return the date for this month.
Expected results (on 4/22/16) from the above would be: '05-18-2016', '05-10-2016', '04-28-2016'.
I'd prefer to do it mathematically and avoid creating a calendar table if possible.
Thanks.
Partial answer, which is by no means bug free.
This doesn't cater for 'Every-' entries, but hopefully will give you some inspiration. I'm sure there are plenty of test cases this will fail on, and you might be better off writing a stored proc.
I did try to do this by calculating the day name and day number of the first day of the month, then calculating the next wanted day and applying an offset, but it got messy. I know you said no date table but the CTE simplifies things.
How it works
A CTE creates a calendar for the current month of date and dayname. Some rather suspect parsing code pulls the day name from the test data and joins to the CTE. The where clause filters to dates greater than the Nth occurrence, and the select adds 4 weeks if the date has passed. Or at least that's the theory :)
I'm using DATEFROMPARTS to simplify the code, which is a SQL 2012 function - there are alternatives on SO for 2008.
SELECT * INTO #TEST FROM (VALUES ('3rd-Wednesday'), ('2nd-Tuesday'), ('4th-Monday')) A(Value)
SET DATEFIRST 1
;WITH DAYS AS (
SELECT
CAST(DATEADD(MONTH,DATEDIFF(MONTH,0,GETDATE()),N.Number) AS DATE) Date,
DATENAME(WEEKDAY, DATEADD(MONTH,DATEDIFF(MONTH,0,GETDATE()),N.Number)) DayName
FROM master..spt_values N WHERE N.type = 'P' AND N.number BETWEEN 0 AND 31
)
SELECT
T.Value,
CASE WHEN MIN(D.Date) < GETDATE() THEN DATEADD(WEEK, 4, MIN(D.DATE)) ELSE MIN(D.DATE) END Date
FROM #TEST T
JOIN DAYS D ON REVERSE(SUBSTRING(REVERSE(T.VALUE), 1, CHARINDEX('-', REVERSE(T.VALUE)) -1)) = D.DayName
WHERE D.Date >=
DATEFROMPARTS(
YEAR(GETDATE()),
MONTH(GETDATE()),
1+ 7*(CAST(SUBSTRING(T.Value, 1,1) AS INT) -1)
)
GROUP BY T.Value
Value Date
------------- ----------
2nd-Tuesday 2016-05-10
3rd-Wednesday 2016-05-18
4th-Monday 2016-04-25
Related
I have such a situation.
I need to have 2 columns 1) Is just pull data from a table (just as it is) r.[RCLDTE] (Day of week)
and 2 column) I need to basically look at the first column and make it Saturday of that week.
SELECT r.[RCLDTE] AS 'Day of Week'
,r.[RCLDTE] AS 'Week Ending Day (Saturday)'
Before what I was doing at similar projects I just used this code and added to WHERE statement.
WHERE CONVERT(DATE, CONVERT(CHAR(8), r.[RCLDTE] )) = cast(DATEADD(dd, DATEPART(DW,GETDATE())*-1, GETDATE()) as date)
This code was changing the dates column to Saturday.
However, here I have a different situation. I need 2 columns 1) as it is and 2) where dates will be Saturdays of the week from r.[RCLDTE] column , as a result from the way how I understand I cannot use WHERE statement because it will affect both columns.
Does someone know how I can leave 1st column as it is and 2nd a column of Saturday.
Please let me know.
Thanks.
To avoid issues when someone changes either DATEFIRST or LANGUAGE settings, you can use this. Also, given that you are storing dates in a numeric column for some reason (you really should provide feedback to whoever owns the system so they can fix it), we have to first try to convert those values to a date (they may not all be valid, which is one of the problems with using the wrong data type):
;WITH t AS
(
SELECT *, ProperDate = CASE WHEN ISDATE(CONVERT(char(8), RCLDTE)) = 1
THEN CONVERT(date, CONVERT(char(8), RCLDTE)) END
FROM dbo.tablename
)
SELECT [Language] = ##language, [Datefirst] = ##datefirst,
RCLDTE = CASE WHEN ProperDate IS NULL THEN RCLDTE END,
[Day of Week] = ProperDate,
[Saturday] = DATEADD
(
DAY,
6 - ((DATEPART(WEEKDAY, ProperDate) + ##DATEFIRST - 1) % 7),
ProperDate
)
FROM t;
Updated db<>fiddle that also demonstrates the handling of garbage data and a version of SQL Server so old that TRY_CONVERT() didn't exist yet (at least 12 years ago).
here is one way :
select
r.RCLDTE AS 'Day of Week'
, dateadd(day, 7 - datepart(weekday, r.RCLDTE) , r.RCLDTE)
from tablename r
db<>fiddle here
I'm trying to find all the saturdays between two dates (inclusive) without using a loop.
For example, April 1, 2021, to May 1, 2021 should return:
04-03-2021
04-10-2021
04-17-2021
04-24-2021
05-01-2021
You can use datename
select *
from Table
where Datename(dw,Datecolumn)='Saturday'
and DateColumn >= start and Datecolumn < End;
Alternatively, if you just want to generate a list on the fly, you can do
declare #StartDate date = '20210401', #EndDate date = '20210501';
select DateAdd(day, rn-1, #StartDate)
from (
select Row_Number() over (order by object_id) rn
from sys.columns
) d
where rn - 1 <= DateDiff(day, #StartDate, #EndDate)
and DateName(dw, DateAdd(day, rn-1, #StartDate))='Saturday';
This first generates a list of numbers in the inner query by utilising one of several possible system tables to select just a row number. This is essentially building a numbers / tally table on the fly, and it's usually a good idea to have a permanent table like this available (a single column of integers starting at 1 and going up to a squintillion or whatever you need). You can see how this works by just highlighting the inner query and running it (F5 in SSMS).
An out query selects from this and filters the row numbers to just the right sequential range for the number of days between the two specified dates. Again, you can check this by highlighting the entire query except for the last line, you'll see it generates the list of dates between the specified start and end dates inclusively.
Finally the and criteria extracts the name of the day for each date and further filters the list of dates based on the day's name.
I'm trying to write a query which can count the number of working days between a payment being received and being processed, I started playing around with this for payments received in December 2017;
select unique trunc(date_received),
(case when trunc(date_received) in ('25-DEC-17','26-DEC-17') Then 0 when
to_char(date_received,'D') <6 Then 1 else 0 end) Working_day
from payments
where date_received between '01-DEC-17' and '31-dec-17'
order by trunc(date_received)
But to be honest, I'm at a loss as to how to take it further and add in date_processed and count the number of working days between date_processed and date_received... Any help would be much appreciated...
Maybe not the most optimal, but it works quite nicely, and it's easy to incorporate more complicated checks, like holidays. This query first generates all dates between the two dates, and then lets you filter out all the days that 'don't count'.
In this implementation I filtered out only weekend days, but it's quite easy to add checks for holidays and such.
with
-- YourQuery: I used a stub, but you can use your actual query here, which
-- returns a from date and to date. If you have multiple rows, you can also
-- output some id here, which can be used for grouping in the last step.
YourQuery as
(
select
trunc(sysdate - 7) as FromDate,
trunc(sysdate) as ToDate
from dual),
-- DaysBetween. This returns all the dates from the start date up to and
-- including the end date.
DaysBetween as
(
select
FromDate,
FromDate + level - 1 as DayBetween,
ToDate
from
YourQuery
connect by
FromDate + level - 1 <= ToDate)
-- As a last step, you can filter out all the days you want.
-- This default query only filters out Saturdays and Sundays, but you
-- could add a 'not exists' check that checks against a table with known
-- holidays.
select
count(*)
from
DaysBetween d
where
trim(to_char(DAYINBETWEEN, 'DAY', 'NLS_DATE_LANGUAGE=AMERICAN'))
not in ('SATURDAY', 'SUNDAY');
I have a Sales table:
id_item, quantity, date_time
What I need is to sum the items sold in a month and divide them by the days of the month from a selected period of months.
Example - The user selects the dates of Oct 1 to Dec 31. I need to show the items_sold/days_of_month:
Month Items sold Days of month Items/Day
Sep 25 30 0.83333
Oct 36 31 1.16
Dec 15 31 0.4838
I have to specify by Kind of item. the kind is obtained from another table called Items. I use dateformat dd/mm/yy.
select
month(date_time),
sum(quantity) / (select(datepart(dd,getdate())))
from
sales v
join items a on v.id_item=a.id_item
where
a.kind='Kind of Item'
and cast(Convert(varchar(10), date_time, 112) as datetime)
between '01/10/2012' and '31/12/2012'
group by
month(date_time)
My problem is selecting the days of the months, how can I select x number of months and divide the sum(quantity) of each month by the days of each?
I know this part of the code only selects the days of the current month:
(select(datepart(dd,getdate())))
Try this on for size:
DECLARE
#FromDate datetime,
#ToDate date; -- inclusive
SET #FromDate = DateAdd(month, DateDiff(month, 0, '20121118'), 0);
SET #ToDate = DateAdd(month, DateDiff(month, 0, '20121220') + 1, 0);
SELECT
Year = Year(S.date_time),
Month = Month(S.date_time),
QtyPerDay =
Sum(s.quantity) * 1.0
/ DateDiff(day, M.MonthStart, DateAdd(month, 1, M.MonthStart))
FROM
dbo.Sales S
INNER JOIN dbo.Items I
ON S.id_item = I.id_item
CROSS APPLY (
SELECT MonthStart = DateAdd(month, DateDiff(month, 0, S.date_time), 0)
) M
WHERE
I.kind = 'Kind of Item'
AND S.date_time >= #FromDate
AND S.date_time < #ToDate
GROUP BY
Year(S.date_time),
Month(S.date_time),
M.MonthStart
It will select any full month that is partially enclosed by the FromDate and ToDate. The * 1.0 part is required if the quantity column is an integer, otherwise you will get an integer result instead of a decimal one.
Some stylistic notes:
Do NOT use string date conversion on a column to ensure you get whole days. This will completely prevent any index from being used, require more CPU, and furthermore is unclear (what does style 112 do again!?!?). To enclose full date periods, use what I showed in my query of DateCol >= StartDate and DateCol < OneMoreThanEndDate. Do a search for "sargable" to understand a very key concept here. A very safe and valuable general rule is to never put a column inside an expression if the condition can be rewritten to avoid it.
It is good that you're aliasing your tables, but you should use those aliases throughout the query for each column, as I did in my query. I recognize that the aliases V and A came from another language so they make sense there--just in general try to use aliases that match the table names.
Do include the schema name on your objects. Not doing so is not a huge no-no, but there are definite benefits and it is best practice.
When you ask a question it is helpful to explain all the logic so people don't have to guess or ask you--if you know (for example) that users can input mid-month dates but you need whole months then please indicate that in your question and state what needs to be done.
Giving the version of SQL server helps us zero in on the syntax required, as prior versions are less expressive. By telling us the version we can give you the best query possible.
Note: there is nothing wrong with putting the date calculation math in the query itself (instead of using SET to do it). But I figured you would be encoding this in a stored procedure and if so, using SET is just fine.
All three statements below return the same result. So I'm struggling to see what the difference is between using dayofyear, day and weekday. Am I missing something or are they all equivalent?
SELECT DATEADD(dayofyear,1,'20111231')
SELECT DATEADD(day,1,'20111231')
SELECT DATEADD(weekday,1,'20111231')
They all return 2012-01-01 00:00:00.000
In that use, no they return the same. Though "day" feels natural for this use.
The difference comes in (e.g.) DATEPART:
SELECT DATEPART(dayofyear,'20111231') -- 365
SELECT DATEPART(day,'20111231') -- 31
SELECT DATEPART(weekday,'20111231') --7
Here's the MSDN ref on it:
dayofyear , day, and weekday return
the same value.
SELECT DATEADD(dayofyear,1,'20111231')
SELECT DATEADD(day,1,'20111231')
SELECT DATEADD(weekday,1,'20111231')
They are all equivalent.
The date parts month, year, day, hour are all units of measure in their own right. However, dayofyear and weekday are not. Yet you can look at it this way -
the datepart "month" changes when the month changes,
the datepart "hour" changes when the hour changes,
the datepart "dayofyear" changes (by 1) when the day changes,
the datepart "weekday" changes (by 1) when the day changes
the datepart "day" changes (by 1) when the day changes
So you have to argue that the "unit of" dayofyear is equal to one day. To DateAdd a "dayofyear" part, it will increase the date by 1 day.
If you are starting with a date variable or date/time column, you can just add 1 to it, e.g.
dateadd(d, 1, #date) == #date + 1
It won't work with date literals
select '2010-12-12' + 1 -- attempts to add the string '2010-12-12' to 1
One would have to cast/convert
select cast('2010-12-12' as datetime) + 1
But by that stage, you might as well use dateadd, which implicitly casts the 3rd argument
select dateadd(d, 1, '2010-12-12') -- 2010-12-13
select dateadd(d, 1, 40522) -- 2010-12-13