Related
How to find the nearest Tuesday by given date previous only in SQL Server?
Example: today is 2018-09-09, the result should be 2018-09-04.
use case when and datepart function and conditionally find nearest Tuesday
select case datepart(dw,getdate()) when 7 then DATEADD(day, -4, getdate())
when 1 then DATEADD(day, -5, getdate())
when 2 then DATEADD(day, -6, getdate())
when 3 then DATEADD(day, -7, getdate())
when 4 then DATEADD(day, -1, getdate())
when 5 then DATEADD(day, -2, getdate())
when 6 then DATEADD(day, -3, getdate())
else getdate() end;
Apparently I misread the question but I'll leave this here in case someone else might find it educational (it also demonstrates how DATEPART( dw, ... ) result can differ by server so hard-coding values as in the above answer may lead to erroneous results depending on environment) - this will calculated the closest date to a specified day of week (whereas the question asked for the previous Tuesday, specifically)...
You're given a date. You want to find the nearest Tuesday so you'll first need to figure out what day of the week the given date represents. Google "mssql day of week" and the first hit is the function you can use to get the day of week. It will be in an integer format, so you'll need to reference which numbers represents which days of the week.
The result will be based on the value of ##DATEFIRST which defines the first day of the week (and the results are a one-based index), so you will need to adjust your target day of week value to align with the server's ##DATEFIRST value. You can do this by subtracting ##DATEFIRST from 7, adding the target day of week value (1: Monday through 7: Sunday), modulo the result by 7 and add 1 to keep at a one-based index:
( 7 - ##DATEFIRST + #targetDayOfWeek ) % 7 + 1
Once you know what day of the week your target date is and what number represents Tuesday, you then calculate the difference in days. If the magnitude is greater than 3, adjust by adding or subtracting 7 to fit into the range [-3, 3].
create function dbo.CalculateClosestDayOfWeekDate
(
#fromDate DATETIME,
#targetDayOfWeek int -- 1: Monday ... 7: Sunday
)
returns DATETIME
as
begin
-- AdjustedTargetDayOfWeek: ( 7 - ##DATEFIRST + #targetDayOfWeek ) % 7 + 1
-- FromDateDayOfWeek: DATEPART( dw, #fromDate )
-- DayOfWeekDiff = AdjustedTargetDayOfWeek - FromDateDayOfWeek
declare #daysToAdd int
set #daysToAdd = ( ( 7 - ##DATEFIRST + #targetDayOfWeek ) % 7 + 1 ) - DATEPART( dw, #fromDate )
-- if the nearest previous day-of-week is all that's wanted,
-- replace the below block with `if( 0 < #daysToAdd)`
-- and subtract 7 from #daysToAdd if true
if( 3 < ABS( #daysToAdd ) ) -- if magnitude greater than 3
begin
if( 3 < #daysToAdd ) -- if positive, subtract 7
begin
set #daysToAdd = #daysToAdd - 7
end
else -- negative, so add 7
begin
set #daysToAdd = #daysToAdd + 7
end
end
return DATEADD( day, #daysToAdd, #fromDate )
end
go
declare #testData table
(
FromDate dateTime,
TargetDayOfWeek int
)
insert #testData values ( '2018-09-08', 2 ) -- target Tuesday from a Saturday
insert #testData values ( '2018-09-08', 3 ) -- target Wednesday from a Saturday
insert #testData values ( '2018-09-09', 3 ) -- target Wednesday from a Sunday
insert #testData values ( '2018-09-09', 4 ) -- target Thursday from a Sunday
insert #testData values ( '2018-09-10', 4 ) -- target Thursday from a Monday
insert #testData values ( '2018-09-10', 5 ) -- target Friday from a Monday
select
td.FromDate
, td.TargetDayOfWeek
, dbo.CalculateClosestDayOfWeekDate( td.FromDate, td.TargetDayOfWeek ) ResultingDate
from
#testData td
Results:
Please try it.
select
case when datepart(dw,getdate()) =7
or datepart(dw,getdate()) =6
or datepart(dw,getdate()) =5
or datepart(dw,getdate()) =4
then DATEADD(day, 3-datepart(dw,getdate()) , getdate())
else DATEADD(day, -4-datepart(dw,getdate()) , getdate())
end;
I am revisiting some old code I wrote for a report when I was still very new to SQL (MSSQL). It does what it is supposed to but its not the prettiest or most efficient.
The dummy code below mimics what I currently have in place. Here I am trying to get counts for the number of contracts that are open over the last 5 weeks. For this example a contract is considered open if the start date of the contract happens before of during the given week and the end date happens during or after the given week.
dbo.GetWeekStart(#Date DATETIME, #NumOfWeeks INT, #FirstDayOfWeek CHAR(3)) is a function that will return the first day of each week based on the date provided for a specified number of weeks. ie SELECT * FROM dbo.GetWeekStart('20120719', -2, 'MON') will return the 2 mondays prior to July 19, 2012.
How can I simplify this? I think there is someone to do this without a loop but I have not been able to figure it out.
DECLARE #RunDate DATETIME,
#Index INT,
#RowCount INT,
#WeekStart DATETIME,
#WeekEnd DATETIME
DECLARE #Weeks TABLE
(
WeekNum INT IDENTITY(0,1),
WeekStart DATETIME,
WeekEnd DATETIME
)
DECLARE #Output TABLE
(
WeekStart DATETIME,
OpenContractCount INT
)
SET #RunDate = GETDATE()
INSERT INTO #Weeks (WeekStart, WeekEnd)
SELECT WeekStart,
DATEADD(ss,-1,DATEADD(ww,1,WeekStart))
FROM dbo.[GetWeekStart](#RunDate, -5, 'MON')
SET #RowCount = (SELECT COUNT(*) FROM #Weeks)
SET #Index = 0
WHILE #Index < #RowCount
BEGIN
SET #WeekStart = (SELECT WeekStart FROM #Weeks WHERE WeekNum = #Idx)
SET #WeekEnd = (SELECT WeekEnd FROM #Weeks WHERE WeekNum = #Idx)
INSERT INTO #Output (WeekStart, OpenContractCount)
SELECT #WeekStart,
COUNT(*)
FROM Contracts c
WHERE c.StartDate <= #WeekEnd
AND ISNULL(c.EndDate, GETDATE()) >= #WeekStart
SET #Index = #Index + 1
END
SELECT * FROM #Output
I see no reason why this wouldn't work:
DECLARE #RunDate DATETIME = GETDATE()
SELECT WeekStart, COUNT(*)
FROM Contracts c
INNER JOIN dbo.[GetWeekStart](#RunDate, -5, 'MON')
ON c.StartDate < DATEADD(WEEK, 1, WeekStart)
AND (c.EndDate IS NULL OR c.EndDate >= #WeekStart)
GROUP BY WeekStart
I am not sure how you are generating your dates within your function, just in case you are using a loop/recursive CTE I'll include a query that doesn't use loops/cursors etc.
DECLARE #RunDate DATETIME = GETDATE()
-- SET DATEFIRST AS 1 TO ENSURE MONDAY IS THE FIRST DAY OF THE WEEK
-- CHANGE THIS TO SIMULATE CHANGING YOUR WEEKDAY INPUT TO db
SET DATEFIRST 1
-- SET RUN DATE TO BE THE START OF THE WEEK
SET #RunDate = CAST(DATEADD(DAY, 1 - DATEPART(WEEKDAY, #RunDate), #RunDate) AS DATE)
;WITH Weeks AS
( SELECT TOP 5 -- CHANGE THIS TO CHANGE THE WEEKS TO RUN
DATEADD(WEEK, 1 - ROW_NUMBER() OVER(ORDER BY Object_ID), #RunDate) [WeekStart]
FROM sys.All_Objects
)
SELECT WeekStart, COUNT(*)
FROM Contracts c
INNER JOIN Weeks
ON c.StartDate < DATEADD(WEEK, 1, WeekStart)
AND (c.EndDate IS NULL OR c.EndDate >= #WeekStart)
GROUP BY WeekStart
Did this quick but it should work
/*CTE generates Start & End Dates for 5 weeks
Start Date = Sunday of week # midnight
End Date = Sunday of next week # midnight
*/
WITH weeks
AS ( SELECT DATEADD(ww, -4,
CAST(FLOOR(CAST(GETDATE() - ( DATEPART(dw,
GETDATE()) - 1 ) AS FLOAT)) AS DATETIME)) AS StartDate
UNION ALL
SELECT DATEADD(wk, 1, StartDate)
FROM weeks
WHERE DATEADD(wk, 1, StartDate) <= GETDATE()
)
SELECT w.StartDate ,
COUNT(*) AS OpenContracts
FROM dbo.Contracts c
LEFT JOIN weeks w ON c.StartDate < DATEADD(d, 7, w.StartDate)
AND ISNULL(c.EndDate, GETDATE()) >= w.StartDate
GROUP BY w.StartDate
Is there is a way to group dates by week of month in SQL Server?
For example
Week 2: 05/07/2012 - 05/13/2012
Week 3: 05/14/2012 - 05/20/2012
but with Sql server statement
I tried
SELECT SOMETHING,
datediff(wk, convert(varchar(6), getdate(), 112) + '01', getdate()) + 1 AS TIME_
FROM STATISTICS_
GROUP BY something, TIME_
ORDER BY TIME_
but it returns the week number of month. (means 3)
How to get the pair of days for current week ?
For example, now we are in third (3rd) week and I want to show 05/14/2012 - 05/20/2012
I solved somehow:
SELECT DATEADD(ww, DATEDIFF(ww,0,<my_column_name>), 0)
select DATEADD(ww, DATEDIFF(ww,0,<my_column_name>), 0)+6
Then I will get two days and I will concatenate them later.
All right, bear with me here. We're going to build a temporary calendar table that represents this month, including the days from before and after the month that fall into your definition of a week (Monday - Sunday). I do this in a lot of steps to try to make the process clear, but I probably haven't excelled at that in this case.
We can then generate the ranges for the different weeks, and you can join against your other tables using that.
SET DATEFIRST 7;
SET NOCOUNT ON;
DECLARE #today SMALLDATETIME, #fd SMALLDATETIME, #rc INT;
SELECT #today = DATEADD(DAY, DATEDIFF(DAY, 0, GETDATE()), 0), -- today
#fd = DATEADD(DAY, 1-DAY(#today), #today), -- first day of this month
#rc = DATEPART(DAY, DATEADD(DAY, -1, DATEADD(MONTH, 1, #fd)));-- days in month
DECLARE #thismonth TABLE (
[date] SMALLDATETIME,
[weekday] TINYINT,
[weeknumber] TINYINT
);
;WITH n(d) AS (
SELECT TOP (#rc+12) DATEADD(DAY, ROW_NUMBER() OVER
(ORDER BY [object_id]) - 7, #fd) FROM sys.all_objects
)
INSERT #thismonth([date], [weekday]) SELECT d, DATEPART(WEEKDAY, d) FROM n;
DELETE #thismonth WHERE [date] < (SELECT MIN([date]) FROM #thismonth WHERE [weekday] = 2)
OR [date] > (SELECT MAX([date]) FROM #thismonth WHERE [weekday] = 1);
;WITH x AS ( SELECT [date], weeknumber, rn = ((ROW_NUMBER() OVER
(ORDER BY [date])-1) / 7) + 1 FROM #thismonth ) UPDATE x SET weeknumber = rn;
-- now, the final query given all that (I've only broken this up to get rid of the vertical scrollbars):
;WITH ranges(w,s,e) AS (
SELECT weeknumber, MIN([date]), MAX([date]) FROM #thismonth GROUP BY weeknumber
)
SELECT [week] = CONVERT(CHAR(10), r.s, 120) + ' - ' + CONVERT(CHAR(10), r.e, 120)
--, SOMETHING , other columns from STATISTICS_?
FROM ranges AS r
-- LEFT OUTER JOIN dbo.STATISTICS_ AS s
-- ON s.TIME_ >= r.s AND s.TIME_ < DATEADD(DAY, 1, r.e)
-- comment this out if you want all the weeks from this month:
WHERE w = (SELECT weeknumber FROM #thismonth WHERE [date] = #today)
GROUP BY r.s, r.e --, SOMETHING
ORDER BY [week];
Results with WHERE clause:
week
-----------------------
2012-05-14 - 2012-05-20
Results without WHERE clause:
week
-----------------------
2012-04-30 - 2012-05-06
2012-05-07 - 2012-05-13
2012-05-14 - 2012-05-20
2012-05-21 - 2012-05-27
2012-05-28 - 2012-06-03
Note that I chose YYYY-MM-DD on purpose. You should avoid regional formatting like M/D/Y especially for input but also for display. No matter how targeted you think your audience is, you're always going to have someone who thinks 05/07/2012 is July 5th, not May 7th. With YYYY-MM-DD there is no ambiguity whatsoever.
Create a calendar table, then you can query week numbers, first/last days of specific weeks and months etc. You can also join on it queries to get a date range etc.
How about a case statement?
case when datepart(day, mydatetime) between 1 and 7 then 1
when datepart(day, mydatetime) between 8 and 14 then 2
...
You'll also have to include the year & month unless you want all the week 1s in the same group.
It's not clear of you want to "group dates by week of month", or alternately "select data from a given week"
If you mean "group" this little snippet should get you 'week of month':
SELECT <stuff>
FROM CP_STATISTICS
WHERE Month(<YOUR DATE COL>) = 5 --april
GROUP BY Year(<YOUR DATE COL>),
Month(<YOUR DATE COL>),
DATEDIFF(week, DATEADD(MONTH, DATEDIFF(MONTH, 0, <YOUR DATE COL>), 0)
, <YOUR DATE COL>) +1
Alternately, if you want "sales for week 1 of April, ordered by date" You could do something like..
DECLARE #targetDate datetime2 = '5/3/2012'
DECLARE #targetWeek int = DATEDIFF(week, DATEADD(MONTH,
DATEDIFF(MONTH, 0, #targetDate), 0), #targetDate) +1
SELECT <stuff>
FROM CP_STATISTICS
WHERE MONTH(#targetDate) = Month(myDateCol) AND
YEAR(#targetDate) = Year (myDateCol) AND
#targetWeek = DATEDIFF(week, DATEADD(MONTH,
DATEDIFF(MONTH, 0, myDateCol), 0), myDateCol) +1
ORDER BY myDateCol
Note, things would get more complicated if you use non-standard weeks, or want to reach a few days into an earlier month for weeks that straddle a month boundary.
EDIT 2
From looking at your 'solved now' section. I think your question is "how do I get data out of a table for a given week?"
Your solution appears to be:
DECLARE #targetDate datetime2 = '5/1/2012'
DECLARE #startDate datetime2 = DATEADD(ww, DATEDIFF(ww,0,targetDate), 0)
DECLARE #endDate datetime2 = DATEADD(ww, DATEDIFF(ww,0,#now), 0)+6
SELECT <stuff>
FROM STATISTICS_
WHERE dateStamp >= #startDate AND dateStamp <= #endDate
Notice how if the date is 5/1 this solution results in a start date of '4/30/2012'. I point this out because your solution crosses month boundaries. This may or may not be desirable.
I have a table called FcData and the data looks like:
Op_Date
2011-02-14 11:53:40.000
2011-02-17 16:02:19.000
2010-02-14 12:53:40.000
2010-02-17 14:02:19.000
I am looking to get the Number of weeks in That Month from Op_Date. So I am looking for output like:
Op_Date Number of Weeks
2011-02-14 11:53:40.000 5
2011-02-17 16:02:19.000 5
2010-02-14 12:53:40.000 5
2010-02-17 14:02:19.000 5
This page has some good functions to figure out the last day of any given month: http://www.sql-server-helper.com/functions/get-last-day-of-month.aspx
Just wrap the output of that function with a DATEPART(wk, last_day_of_month) call. Combining it with an equivalent call for the 1st-day-of-week will let you get the number of weeks in that month.
Use this to get the number of week for ONE specific date. Replace GetDate() by your date:
declare #dt date = cast(GetDate() as date);
declare #dtstart date = DATEADD(day, -DATEPART(day, #dt) + 1, #dt);
declare #dtend date = dateadd(DAY, -1, DATEADD(MONTH, 1, #dtstart));
WITH dates AS (
SELECT #dtstart ADate
UNION ALL
SELECT DATEADD(day, 1, t.ADate)
FROM dates t
WHERE DATEADD(day, 1, t.ADate) <= #dtend
)
SELECT top 1 DatePart(WEEKDAY, ADate) weekday, COUNT(*) weeks
FROM dates d
group by DatePart(WEEKDAY, ADate)
order by 2 desc
Explained: the CTE creates a result set with all dates for the month of the given date. Then we query the result set, grouping by week day and count the number of occurrences. The max number will give us how many weeks the month overlaps (premise: if the month has 5 Mondays, it will cover five weeks of the year).
Update
Now, if you have multiple dates, you should tweak accordingly, joining your query with the dates CTE.
Here is my take on it, might have missed something.
In Linq:
from u in TblUsers
let date = u.CreateDate.Value
let firstDay = new DateTime(date.Year, date.Month, 1)
let lastDay = firstDay.AddMonths(1)
where u.CreateDate.HasValue
select Math.Ceiling((lastDay - firstDay).TotalDays / 7)
And generated SQL:
-- Region Parameters
DECLARE #p0 Int = 1
DECLARE #p1 Int = 1
DECLARE #p2 Float = 7
-- EndRegion
SELECT CEILING(((CONVERT(Float,CONVERT(BigInt,(((CONVERT(BigInt,DATEDIFF(DAY, [t3].[value], [t3].[value2]))) * 86400000) + DATEDIFF(MILLISECOND, DATEADD(DAY, DATEDIFF(DAY, [t3].[value], [t3].[value2]), [t3].[value]), [t3].[value2])) * 10000))) / 864000000000) / #p2) AS [value]
FROM (
SELECT [t2].[createDate], [t2].[value], DATEADD(MONTH, #p1, [t2].[value]) AS [value2]
FROM (
SELECT [t1].[createDate], CONVERT(DATETIME, CONVERT(NCHAR(2), DATEPART(Month, [t1].[value])) + ('/' + (CONVERT(NCHAR(2), #p0) + ('/' + CONVERT(NCHAR(4), DATEPART(Year, [t1].[value]))))), 101) AS [value]
FROM (
SELECT [t0].[createDate], [t0].[createDate] AS [value]
FROM [tblUser] AS [t0]
) AS [t1]
) AS [t2]
) AS [t3]
WHERE [t3].[createDate] IS NOT NULL
According to this MSDN article: http://msdn.microsoft.com/en-us/library/ms174420.aspx you can only get the current week in the year, not what that month returns.
There may be various approaches to implementing the idea suggested by #Marc B. Here's one, where no UDFs are used but the first and the last days of month are calculated directly:
WITH SampleData AS (
SELECT CAST('20110214' AS datetime) AS Op_Date
UNION ALL SELECT '20110217'
UNION ALL SELECT '20100214'
UNION ALL SELECT '20100217'
UNION ALL SELECT '20090214'
UNION ALL SELECT '20090217'
),
MonthStarts AS (
SELECT
Op_Date,
MonthStart = DATEADD(DAY, 1 - DAY(Op_Date), Op_Date)
/* alternatively: DATEADD(MONTH, DATEDIFF(MONTH, 0, Op_Date), 0) */
FROM FcData
),
Months AS (
SELECT
Op_Date,
MonthStart,
MonthEnd = DATEADD(DAY, -1, DATEADD(MONTH, 1, MonthStart))
FROM FcData
)
Weeks AS (
SELECT
Op_Date,
StartWeek = DATEPART(WEEK, MonthStart),
EndWeek = DATEPART(WEEK, MonthEnd)
FROM MonthStarts
)
SELECT
Op_Date,
NumberOfWeeks = EndWeek - StartWeek + 1
FROM Weeks
All calculations could be done in one SELECT, but I chose to split them into steps and place every step in a separate CTE so it could be seen better how the end result was obtained.
You can get number of weeks per month using the following method.
Datepart(WEEK,
DATEADD(DAY,
-1,
DATEADD(MONTH,
1,
DATEADD(DAY,
1 - DAY(GETDATE()),
GETDATE())))
-
DATEADD(DAY,
1 - DAY(GETDATE()),
GETDATE())
+1
)
Here how you can get accurate amount of weeks:
DECLARE #date DATETIME
SET #date = GETDATE()
SELECT ROUND(cast(datediff(day, dateadd(day, 1-day(#date), #date), dateadd(month, 1, dateadd(day, 1-day(#date), #date))) AS FLOAT) / 7, 2)
With this code for Sep 2014 you'll get 4.29 which is actually true since there're 4 full weeks and 2 more days.
I have to calculate all the invoices which have been paid in the first 'N' days of a month. I have two tables
. INVOICE: it has the invoice information. The only field which does matter is called 'datePayment'
. HOLYDAYS: It is a one column table. Entries at this table are of the form "2009-01-01",
2009-05-01" and so on.
I should consider also Saturdays and Sundays
(this might be not a problem because I could insert those days at the Hollidays table in order to consider them as hollidays if neccesary)
The problem is to calculate which is the 'payment limit'.
select count(*) from invoice
where datePayment < PAYMENTLIMIT
My question is how to calculate this PAYMENTLIMIT. Where PAYMENTLIMIT is 'the fifth working day of every month'.
The query should be run under Mysql and Oracle therefore standard SQL should be used.
Any hint?
EDIT
In order to be consistent with the title of the question the pseudo-query should the read as follows:
select count(*) from invoice
where datePayment < FIRST_WORKING_DAY + N
then the question can be reduced to calculate the FIRST_WORKING_DAY of every month.
You could look for the first date in a month, where the date is not in the holiday table and the date is not a weekend:
select min(datePayment), datepart(mm, datePayment)
from invoices
where datepart(dw, datePayment) not in (1,7) --day of week
and not exists (select holiday from holidays where holiday = datePayment)
group by datepart(mm, datePayment) --monthnr
Something like this might work:
create function dbo.GetFirstWorkdayOfMonth(#Year INT, #Month INT)
returns DATETIME
as begin
declare #firstOfMonth VARCHAR(20)
SET #firstOfMonth = CAST(#Year AS VARCHAR(4)) + '-' + CAST(#Month AS VARCHAR) + '-01'
declare #currDate DATETIME
set #currDate = CAST(#firstOfMonth as DATETIME)
declare #weekday INT
set #weekday = DATEPART(weekday, #currdate)
-- 7 = saturday, 1 = sunday
while #weekday = 1 OR #weekday = 7
begin
set #currDate = DATEADD(DAY, 1, #currDate)
set #weekday = DATEPART(weekday, #currdate)
end
return #currdate
end
I'm not 100% sure about whether the "weekday" numbers are fixed or might depend on your locale on your SQL Server. Check it out!
Marc
Rather than a Holidays table of days to exclude, we use the calendar table approach: one row for every day the application will ever need (thirty years spans a modest 11K rows). So not only does it have an is_weekday column, it has other things relevant to the enterprise e.g. julianized_date. This way, every possible date would have a ready-prepared value for first_working_day_this_month and finding it involves a simple lookup (which SQL products tend to be optimized for!) rather than 'calculating' it each time on the fly.
We have dates table in our application (filled with all dates and date parts for some tens of years), what allows various "missing" date manipulations, like (in pseudo-sql):
select min(ourdates.datevalue)
from ourdates
where ourdates.year=<given year> and ourdates.month=<given month>
and ourdates.isworkday
and not exists (
select * from holidays
where holidays.datevalue=ourdates.datevalue
)
Ok, at a first stab, you could put the following code into a UDF and pass in the Year and Month as variables. It can then return TestDate which is the first working day of the month.
DECLARE #Month INT
DECLARE #Year INT
SELECT #Month = 5
SELECT #Year = 2009
DECLARE #FirstDate DATETIME
SELECT #FirstDate = CONVERT(varchar(4), #Year) + '-' + CONVERT(varchar(2), #Month) + '-' + '01 00:00:00.000'
DROP TABLE #HOLIDAYS
CREATE TABLE #HOLIDAYS (HOLIDAY DateTime)
INSERT INTO #HOLIDAYS VALUES('2009-01-01 00:00:00.000')
INSERT INTO #HOLIDAYS VALUES('2009-05-01 00:00:00.000')
DECLARE #DateFound BIT
SELECT #DateFound = 0
WHILE(#DateFound = 0)
BEGIN
IF(
DATEPART(dw, #FirstDate) = 1
OR
DATEPART(dw, #FirstDate) = 1
OR
EXISTS(SELECT * FROM #HOLIDAYS WHERE HOLIDAY = #FirstDate)
)
BEGIN
SET #FirstDate = DATEADD(dd, 1, #FirstDate)
END
ELSE
BEGIN
SET #DateFound = 1
END
END
SELECT #FirstDate
The things I don`t like with this solution though are, if your holidays table contains all days of the month there will be an infinite loop. (You could check the loop is still looking at the right month) It relies upon the dates being equal, eg all at time 00:00:00. Finally, the way I calculate the 1st of the month past in using string concatenation was a short cut. There are much better ways of finding the actual first day of the month.
Gets the first N working days of each month of year 2009:
select * from invoices as x
where
datePayment between '2009-01-01' and '2009-12-31'
and exists
(
select
1
from invoices
where
-- exclude holidays and sunday saturday...
(
datepart(dw, datePayment) not in (1,7) -- day of week
/*
-- Postgresql and Oracle have programmer-friendly IN clause
and
(datepart(yyyy,datePayment), datepart(mm,datePayment))
not in (select hyear, hday from holidays)
*/
-- this is the MSSQL equivalent of programmer-friendly IN
and
not exists
(
select * from holidays
where
hyear = datepart(yyyy,datePayment)
and hmonth = datepart(mm, datePayment)
)
)
-- ...exclude holidays and sunday saturday
-- get the month of x datePayment
and
(datepart(yyyy, datePayment) = datepart(yyyy, x.datePayment)
and datepart(mm, datePayment) = datepart(mm, x.datePayment))
group by
datepart(yyyy, datePayment), datepart(mm, datePayment)
having
x.datePayment < MIN(datePayment) + #N -- up to N working days
)
Returns the first Monday of the current month
SELECT DATEADD(
WEEK,
DATEDIFF( --x weeks between 1900-01-01 (Monday) and inner result
WEEK,
0, --1900-01-01
DATEADD( --inner result
DAY,
6 - DATEPART(DAY, GETDATE()),
GETDATE()
)
),
0 --1900-01-01 (Monday)
)
SELECT DATEADD(day, DATEDIFF (day, 0, DATEADD (month, DATEDIFF (month, 0, GETDATE()), 0) -1)/7*7 + 7, 0);
select if(weekday('yyyy-mm-01') < 5,'yyyy-mm-01',if(weekday('yyyy-mm-02') < 5,'yyyy-mm-02','yyyy-mm-03'))
Saturdays and Sundays are 5, 6 so you only need two checks to get the first working day