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Hi All,
I need to find average week day count on a monthly basis. My table has the creation date as a field which logs when a query was fired.
Eg. start date  1/15/2008; end date  2/12/2009
I am able to calculate the actual count of queries fired on each Monday,Tuesday... for the above time range on a monthly basis.
I am stuck at a point where I need to find the actual no. of Mondays, Tuesdays .. per month for the given time range.
Any help is welcome.
TIA, Nikhil




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Database  > LogBase Database Columns  > CreationDate, Text
My Query to to calculate the actual count of queries fired on each Monday,Tuesday... for the above time range on a monthly basis.
SELECT DATENAME(month, CreationDate) as DayName,DATENAME(dw, CreationDate) as DayName ,count(*) as ActualCount FROM LogBase Where CreationDate between @fromDate and @toDate and DATENAME(dw, CreationDate) group by DATENAME(dw, CreationDate)
So here I am able to get number of queries/transaction done on each Monday,Tuesday,.. monthwise.
What I am stuck at is how to I calculate the actual no. of Mondays, Tuesdays .. per month for the given time range. (say range is from 3june2008 to 7July2008. So here no. of mondays in June would be 4 and no. of Mondays in July would be 1). I need this data so that I can calculate Average WeeKday Transactions on a monthly bias




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Create this function and call it from your query passing it dbo.udf_NumXWeekDaysinMonth(CreationDate)
CREATE Function dbo.udf_NumXWeekDaysinMonth(@Date datetime) RETURNS smallint AS BEGIN Declare @dte varchar(10) Declare @TestDate varchar(10)
Declare @i smallint Declare @iNumDays smallint
Set @dte = Convert(varchar(10),@Date,101) Set @i = 1 Set @iNumDays = 0
While @i < 32 Begin Set @TestDate = cast(month(@dte) as varchar(2)) + '/' + cast(@i as varchar(2)) + '/' + Cast(Year(@dte) as varchar(4)) print @TestDate IF isdate(@TestDate) = 1 BEGIN IF (DATENAME(dw, @TestDate) = DATENAME(dw, @dte)) BEGIN Set @iNumDays = @iNumDays + 1 END END
Set @i = @i+1 End Return @iNumDays END
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The formula in the following article will calculate weekdays without a loop. There is, however, no consideration for holidays...
http://www.sqlservercentral.com/articles/Advanced+Querying/calculatingworkdays/1660/
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For accurate counts of weekdays, I HIGHLY recommend a calendar table. That way, you can include holidays, etc.
create table Calendar ( Date datetime primary key, constraint CK_Date_NoTime check (Date = cast(cast(cast(date as float) as int) as datetime)), Workday bit not null, Year as datepart(year, date), Month as datepart(month, date), Day as datepart(day, date), WeekDay as datepart(weekday, date)) go insert into dbo.Calendar (Date, Workday) select dateadd(day, number, '1/1/2000'), case when datepart(weekday, dateadd(day, number, '1/1/2000')) between 2 and 6 then 1 else 0 end from dbo.numbers  A table of 10thousand numbers go create index IDX_Calendar_MonthDay on dbo.Calendar(month, day) go update dbo.Calendar set workday = 0 where month = 7 and day = 4 or ...  fill in other holidays here go select count(*) from dbo.Calendar where workday = 1 and date between '5/20/2008' and '6/9/2008'
With a table like that, you can easily have SQL do things like calculate the 1st Monday in September, or the 4th Thursday in November, record these things as holidays, and calculate workdays between dates.
;with Thanksgiving (Row, Date, Workday) as (select row_number() over (order by date), date, workday from dbo.Calendar where Month = 11 and WeekDay = 5) update Thanksgiving set workday = 0 where row = 4
You can also add more indexes to it, if you so desire.
Using a 10thousand day calendar starting from 1 Jan 2000, will give you a table that goes into 2027, which should be enough to start with. As needed, add more, or create a job that runs on the first day of each year and adds another year worth of days (if you do that, make sure it adds enough to account for leap years).
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GSquared (6/9/2008)
For accurate counts of weekdays, I HIGHLY recommend a calendar table. That way, you can include holidays, etc. create table Calendar ( Date datetime primary key, constraint CK_Date_NoTime check (Date = cast(cast(cast(date as float) as int) as datetime)), Workday bit not null, Year as datepart(year, date), Month as datepart(month, date), Day as datepart(day, date), WeekDay as datepart(weekday, date)) go insert into dbo.Calendar (Date, Workday) select dateadd(day, number, '1/1/2000'), case when datepart(weekday, dateadd(day, number, '1/1/2000')) between 2 and 6 then 1 else 0 end from dbo.numbers  A table of 10thousand numbers go create index IDX_Calendar_MonthDay on dbo.Calendar(month, day) go update dbo.Calendar set workday = 0 where month = 7 and day = 4 or ...  fill in other holidays here go select count(*) from dbo.Calendar where workday = 1 and date between '5/20/2008' and '6/9/2008'
With a table like that, you can easily have SQL do things like calculate the 1st Monday in September, or the 4th Thursday in November, record these things as holidays, and calculate workdays between dates. ;with Thanksgiving (Row, Date, Workday) as (select row_number() over (order by date), date, workday from dbo.Calendar where Month = 11 and WeekDay = 5) update Thanksgiving set workday = 0 where row = 4
You can also add more indexes to it, if you so desire. Using a 10thousand day calendar starting from 1 Jan 2000, will give you a table that goes into 2027, which should be enough to start with. As needed, add more, or create a job that runs on the first day of each year and adds another year worth of days (if you do that, make sure it adds enough to account for leap years).
Using the code above I came up with the code below for adding company holidays:
How do I do it without using a cursor?
http://www.sqlservercentral.com/Forums/Topic5133151491.aspx#bm513318
IF OBJECT_ID('Calendar', 'U') IS NOT NULL DROP TABLE Calendar
create table Calendar ( Date datetime primary key, constraint CK_Date_NoTime check (Date = cast(cast(cast(date as float) as int) as datetime)), Workday bit not null, Year as datepart(year, date), Month as datepart(month, date), Day as datepart(day, date), WeekDay as datepart(weekday, date), LongDay as datename(weekday, date), DayType varchar(50)) go
create table Numbers ( Num_ID int) DECLARE @Numbers TABLE ( Num_ID INT )
declare @number as int set @number =1 while @number <10001 begin insert into @Numbers (num_id) values (@number) set @number=@number+1 end
insert into dbo.Calendar (Date, Workday,DayType) select dateadd(day, num_id, '12/31/1999'), case when datepart(weekday, dateadd(day, num_id, '12/31/1999')) between 2 and 6 then 1 else 0 end, case when datepart(weekday, dateadd(day, num_id, '12/31/1999')) between 2 and 6 then 'Work' else 'Weekend' end from @Numbers  A table of 10thousand numbers go create index IDX_Calendar_MonthDay on dbo.Calendar(month, day) go
update dbo.Calendar set workday = 0, DayType='New Years Day' where month = 1 and day = 1 go update dbo.Calendar set workday = 0, DayType='Independance Day' where month = 7 and day = 4 go update dbo.Calendar set workday = 0, DayType='Christmas Day' where month = 12 and day = 25 go
DECLARE @CalendarYear TABLE ( [Year] INT )
DECLARE @year int
INSERT INTO @CalendarYear select distinct year from calendar order by year
DECLARE cYear CURSOR FOR SELECT year FROM @CalendarYear
OPEN cYear
fetch cYear into @year while @@fetch_status=0 begin update dbo.Calendar set workday = 0, DayType='Memorial Day' where date=(select max(date) from calendar where month =5 and year=@year and weekday=2) update dbo.Calendar set workday = 0, DayType='Labor Day' where date=(select min(date) from calendar where month =9 and year=@year and weekday=2) update dbo.Calendar set workday = 0, DayType='Thanksgiving Day' where date=(select max(date)1 from calendar where month =11 and year=@year and weekday=6) update dbo.Calendar set workday = 0, DayType='Day after Thanksgiving Day' where date=(select max(date) from calendar where month =11 and year=@year and weekday=6)
fetch cYear into @year
end close cYear
/*
1st Jan New Year's Day Last Monday in May Memorial Day 4th Jul Independence Day First Monday in September Labor Day Fourth Thursday in November Thanksgiving Day 25th Dec Christmas Day
*/




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I would just wrap your code in () and use it as a type of derived table and average the counts like this...
select MonthName, Dayname, Average(actualCount) from ( SELECT CreationDate,DATENAME(month, CreationDate) as MonthName,DATENAME(dw, CreationDate) as DayName ,count(*) as ActualCount FROM LogBase Where CreationDate between @fromDate and @toDate group by CreationDate, DATENAME(month, CreationDate),DATENAME(dw, CreationDate) ) as a group by MonthName, Dayname




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Stephen Yale (6/18/2008) ..... How do I do it without using a cursor? .....
Here's one way:
CREATE FUNCTION [dbo].[IF_Calendar] ( @StartDate DATE, @EndDate DATE, @FirstWeekDay VARCHAR(10) ) RETURNS TABLE WITH SCHEMABINDING AS RETURN (  inline tally table WITH E1(N) AS ( SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 ), 10E+1 or 10 rows E2(N) AS (SELECT 1 FROM E1 a CROSS JOIN E1 b), 10E+2 or 100 rows E3(N) AS (SELECT 1 FROM E2 a CROSS JOIN E2 b), 10E+4 or 10,000 rows max
iTally AS (  generate sufficient rows to cover startdate to enddate inclusive SELECT TOP(1+DATEDIFF(DAY,@StartDate,@EndDate)) rn = ROW_NUMBER() OVER(ORDER BY (SELECT NULL))1 FROM E3 )
 Do some date arithmetic SELECT a.DateRange, c.[Year], c.[Month], c.[DayOfMonth], c.AbsWeekno, c.[DayName], d.Holiday FROM iTally CROSS APPLY (SELECT DateRange = DATEADD(day,rn,@StartDate)) a CROSS APPLY (VALUES ('Tuesday',1),('Wednesday',2),('Thursday',3),('Friday',4),('Saturday',5),('Sunday',6),('Monday',7) ) b (FirstWeekDay, FirstWeekdayOffset) CROSS APPLY ( SELECT [Year] = YEAR(a.DateRange), [Month] = MONTH(a.DateRange), [DayOfMonth] = DAY(a.DateRange), AbsWeekno = DATEDIFF(day,FirstWeekdayOffset,a.DateRange)/7, [DayName] = DATENAME(weekday,a.DateRange) ) c CROSS APPLY ( SELECT Holiday = CASE WHEN [Month] = 1 AND [DayOfMonth] = 1 THEN 'New Year' WHEN [Month] = 5 AND [DayOfMonth] >= 25 AND [DayName] = 'Monday' THEN 'Memorial Day' WHEN [Month] = 7 AND [DayOfMonth] = 4 THEN 'Independence Day' WHEN [Month] = 9 AND [DayOfMonth] <= 7 AND [DayName] = 'Monday' THEN 'Labor Day' WHEN [Month] = 11 AND [DayOfMonth] BETWEEN 22 AND 28 AND [DayName] = 'Thursday' THEN 'Thanksgiving Day' WHEN [Month] = 12 AND [DayOfMonth] = 25 THEN 'Christmas Day' ELSE NULL END ) d WHERE b.FirstWeekDay = @FirstWeekDay
)
^{“Write the query the simplest way. If through testing it becomes clear that the performance is inadequate, consider alternative query forms.”  Gail Shaw}
For fast, accurate and documented assistance in answering your questions, please read this article. Understanding and using APPLY, (I) and (II) Paul White Hidden RBAR: Triangular Joins / The "Numbers" or "Tally" Table: What it is and how it replaces a loop Jeff Moden Exploring Recursive CTEs by Example Dwain Camps



