Test data:
id date company location
----------------------------------
1 03/01/2016 ABC india
2 03/25/2016 ABC us
3 02/24/2016 ABC india
4 02/25/2016 ABC us
5 03/02/2016 ABC india
Query #1
select count(id)
from table
where company = 'ABC'
and date between 03/01/2016 and 03/31/2016
Query #2
select count(id)
from table
where company = 'ABC'
and date between 02/01/2016 and 02/29/2016
Need to calculate location wise count for current and previous months.
How to write a SQL query to return location wise like the below in one query?
Expected result:
company currentmonth Previousmonth location
ABC 2 1 india
ABC 1 1 us
Try:
select company,
sum(case when month(date)=month(getdate())
then 1 else 0 end) as currentMonth,
sum(case when month(date)=month(dateadd(MONTH,-1,getdate()))
then 1 else 0 end) as Previuosmonth,
location
from yourTable
where month(date) between month(dateadd(MONTH,-1,getdate())) and month(getdate())
AND company='ABC'
group by company, location
Since you made two queries and filter both with current month (march) and previous. I decided to use the function MONTH to extract the month from the current date (getdate()) of the system and subtract 1 that way you will always have the current month and the previous one.
EDIT
As pointed out by #DhananjayaKuppu I fixed the problem for when you have a month as January, since the month function returns an integer it would return 0 in my calculation. Now it is fixed.
You may try some thing like subtract current date yearmm format (ex: 201603) and yearmm format of date from table (ex:201603) if it result to 0 treat as current month, else previous month, hope it will help:
SELECT company,
location,
sum(iif(d = 0, 0, 1)) cm,
sum(iif(d = 0, 1, 0)) pm
FROM (SELECT company,
location,
CONVERT(INT,
CONVERT(CHAR(4), GetDate(), 120) +
CONVERT(CHAR(2), GetDate(), 101)
) -
CONVERT(INT,
CONVERT(CHAR(4), date, 120) +
CONVERT(CHAR(2), date, 101)
) as d
FROM table) vw
GROUP BY company, location
Related
I have written the following query in SQL Server
(QUERY)
select ISNULL(count(WORKHOUR) ,'-') AS present,
ISNULL((count(*)-count(WORKHOUR)),'-') AS absent,
ISNULL(cast(SUM(DateDiff(MINUTE, CAST('0:00' as time), WORKHOUR))/60 as nvarchar(3)) + ':' + cast(SUM(DateDiff(MINUTE, CAST('0:00' as time), WORKHOUR))%60 as nvarchar(2)),'-') AS TOTALWRKHRS,
ISNULL(cast(AVG(DateDiff(MINUTE, CAST('0:00' as time), WORKHOUR))/60 as nvarchar(3)) + ':' + cast(AVG(DateDiff(MINUTE, CAST('0:00' as time), WORKHOUR))%60 as nvarchar(2)),'-') AS AVGWRKHRS
from "+**currMonthVal**+" m,"+**currYearVal**+" e WHERE E.EMPID=M.EMPID AND E.LOCATION=M.LOCATION AND M.EMPID = ?
and DATENAME(WEEKDAY, attdate) not IN ('Saturday', 'Sunday') and CONVERT(VARCHAR(10),ATTDATE,3) not in ("+**resultantHL**+")
where currMonthVal and currYearVal are Month and Year values passed from outside and resultantHL are the holiday_dates (like '24/12/2016','25/12/2016') passed from outside.
This query works fine.
I have a table named WORKING_DAYS as follows:'
COLUMN_ID COLUMN_NAME DATA_TYPE
---------------------------------------
1 ID NUMBER
2 WDATE DATE
3 INSTITUTE_ID NUMBER
and sample data in table is:
COLUMN_ID WDATE INSTITUTE_ID
---------------------------------------
1 05-12-15 1
2 19-11-16 1
These two dates in table are actually declared as extra working days in respective months and fall on either Saturday or Sunday.
My requirement is :
I have excluded all Saturday and Sunday from the month in the query above [using DATENAME(WEEKDAY, attdate) not IN ('Saturday', 'Sunday')] but I do not want to exclude the above two dates in WORKING_DAYS table but include them
And I want to do that in the same query if possible as that too in WHERE clause.
How can I do so?
Note: I have already retrieved the extra working days from WORKING_DAYS table and stored in a string variable and wish to pass that variable value in the condition
An OR your date is also on WORKING_DAYS should suffice :
Replace
DATENAME(WEEKDAY, attdate) not IN ('Saturday', 'Sunday')
by
(DATENAME(WEEKDAY, attdate) not IN ('Saturday', 'Sunday') or adddate in (select wdate from WORKING_DAYS))
Here is a weird one for you all.
I need to determine the number of days in a Month
;WITH cteNetProfit AS
(
---- NET PROFIT
SELECT DT.CreateDate
, SUM(DT.Revenue) as Revenue
, SUM(DT.Cost) as Cost
, SUM(DT.GROSSPROFIT) AS GROSSPROFIT
FROM
(
SELECT CAST([createDTG] AS DATE) as CreateDate
, SUM(Revenue) as Revenue
, SUM(Cost) as Cost
, SUM(REVENUE - COST) AS GROSSPROFIT
FROM [dbo].[CostRevenueSpecific]
WHERE CAST([createDTG] AS DATE) > CAST(GETDATE() - 91 AS DATE)
AND CAST([createDTG] AS DATE) <= CAST(GETDATE() - 1 AS DATE)
GROUP BY createDTG
UNION ALL
SELECT CAST([CallDate] AS DATE) AS CreateDate
, SUM(Revenue) as Revenue
, SUM(Cost) as Cost
, SUM(REVENUE - COST) AS GROSSPROFIT
FROM abc.PublisherCallByDay
WHERE CAST([CallDate] AS DATE) > CAST(GETDATE() - 91 AS DATE)
AND CAST([CallDate] AS DATE) <= CAST(GETDATE() - 1 AS DATE)
GROUP BY CALLDATE
) DT
GROUP BY DT.CreateDate
)
select distinct MONTH(CREATEDATE), DateDiff(Day,CreateDate,DateAdd(month,1,CreateDate))
FROM cteNetProfit
For some reason it is returning two different results for the month of March 2016 one result is 30 and the other 31(which of course is correct) I validate that the underlying data only has 31 days worth of data for the Month of March. Since Feb is a leap year can this affect the DATEDIFF function. The remaining months return the correct #.
2 29
3 31
3 30
4 30
5 31
Thanks for the input, however, I found the solution elsewhere
select Distinct MONTH(CREATEDATE), Day(EOMONTH(CreateDate))
FROM cteNetProfit
The difference comes when you hit the 2016-03-31 date. If you run the query below for 2016-03-30 and 2016-03-31, the results of adding 1 MONTH using DATEADD, in both instances, is 2016-04-30. It returns the last day of the next month.
SELECT DATEADD(MONTH,1,'2016-03-30') , DATEADD(MONTH,1,'2016-03-31')
This syntax seemed to work (courtesy of https://raresql.com/2013/01/06/sql-server-get-number-of-days-in-month/).
SELECT DAY(DATEADD(ms,-2,DATEADD(MONTH, DATEDIFF(MONTH,0,#DATE)+1,0))) AS [Current Month]
I have a table in MSSQL with the following structure:
PersonId
StartDate
EndDate
I need to be able to show the number of distinct people in the table within a date range or at a given date.
As an example i need to show on a daily basis the totals per day, e.g. if we have 2 entries on the 1st June, 3 on the 2nd June and 1 on the 3rd June the system should show the following result:
1st June: 2
2nd June: 5
3rd June: 6
If however e.g. on of the entries on the 2nd June also has an end date that is 2nd June then the 3rd June result would show just 5.
Would someone be able to assist with this.
Thanks
UPDATE
This is what i have so far which seems to work. Is there a better solution though as my solution only gets me employed figures. I also need unemployed on another column - unemployed would mean either no entry in the table or date not between and no other entry as employed.
CREATE TABLE #Temp(CountTotal int NOT NULL, CountDate datetime NOT NULL);
DECLARE #StartDT DATETIME
SET #StartDT = '2015-01-01 00:00:00'
WHILE #StartDT < '2015-08-31 00:00:00'
BEGIN
INSERT INTO #Temp(CountTotal, CountDate)
SELECT COUNT(DISTINCT PERSON.Id) AS CountTotal, #StartDT AS CountDate FROM PERSON
INNER JOIN DATA_INPUT_CHANGE_LOG ON PERSON.DataInputTypeId = DATA_INPUT_CHANGE_LOG.DataInputTypeId AND PERSON.Id = DATA_INPUT_CHANGE_LOG.DataItemId
LEFT OUTER JOIN PERSON_EMPLOYMENT ON PERSON.Id = PERSON_EMPLOYMENT.PersonId
WHERE PERSON.Id > 0 AND DATA_INPUT_CHANGE_LOG.Hidden = '0' AND DATA_INPUT_CHANGE_LOG.Approved = '1'
AND ((PERSON_EMPLOYMENT.StartDate <= DATEADD(MONTH,1,#StartDT) AND PERSON_EMPLOYMENT.EndDate IS NULL)
OR (#StartDT BETWEEN PERSON_EMPLOYMENT.StartDate AND PERSON_EMPLOYMENT.EndDate) AND PERSON_EMPLOYMENT.EndDate IS NOT NULL)
SET #StartDT = DATEADD(MONTH,1,#StartDT)
END
select * from #Temp
drop TABLE #Temp
You can use the following query. The cte part is to generate a set of serial dates between the start date and end date.
DECLARE #ViewStartDate DATETIME
DECLARE #ViewEndDate DATETIME
SET #ViewStartDate = '2015-01-01 00:00:00.000';
SET #ViewEndDate = '2015-02-25 00:00:00.000';
;WITH Dates([Date])
AS
(
SELECT #ViewStartDate
UNION ALL
SELECT DATEADD(DAY, 1,Date)
FROM Dates
WHERE DATEADD(DAY, 1,Date) <= #ViewEndDate
)
SELECT [Date], COUNT(*)
FROM Dates
LEFT JOIN PersonData ON Dates.Date >= PersonData.StartDate
AND Dates.Date <= PersonData.EndDate
GROUP By [Date]
Replace the PersonData with your table name
If startdate and enddate columns can be null, then you need to add
addditional conditions to the join
It assumes one person has only one record in the same date range
You could do this by creating data where every start date is a +1 event and end date is -1 and then calculate a running total on top of that.
For example if your data is something like this
PersonId StartDate EndDate
1 20150101 20150201
2 20150102 20150115
3 20150101
You first create a data set that looks like this:
EventDate ChangeValue
20150101 +2
20150102 +1
20150115 -1
20150201 -1
And if you use running total, you'll get this:
EventDate Total
2015-01-01 2
2015-01-02 3
2015-01-15 2
2015-02-01 1
You can get it with something like this:
select
p.eventdate,
sum(p.changevalue) over (order by p.eventdate asc) as total
from
(
select startdate as eventdate, sum(1) as changevalue from personnel group by startdate
union all
select enddate, sum(-1) from personnel where enddate is not null group by enddate
) p
order by p.eventdate asc
Having window function with sum() requires SQL Server 2012. If you're using older version, you can check other options for running totals.
My example in SQL Fiddle
If you have dates that don't have any events and you need to show those too, then the best option is probably to create a separate table of dates for the whole range you'll ever need, for example 1.1.2000 - 31.12.2099.
-- Edit --
To get count for a specific day, it's possible use the same logic, but just sum everything up to that day:
declare #eventdate date
set #eventdate = '20150117'
select
sum(p.changevalue)
from
(
select startdate as eventdate, 1 as changevalue from personnel
where startdate <= #eventdate
union all
select enddate, -1 from personnel
where enddate < #eventdate
) p
Hopefully this is ok, can't test since SQL Fiddle seems to be unavailable.
I am creating a query to give number of days between two days based on year. Actually I have below type of date range
From Date: TO_DATE('01-Jun-2011','dd-MM-yyyy')
To Date: TO_DATE('31-Dec-2013','dd-MM-yyyy')
My Result should be:
Year Number of day
------------------------------
2011 XXX
2012 XXX
2013 XXX
I've tried below query
WITH all_dates AS
(SELECT start_date + LEVEL - 1 AS a_date
FROM
(SELECT TO_DATE ('21/03/2011', 'DD/MM/YYYY') AS start_date ,
TO_DATE ('25/06/2013', 'DD/MM/YYYY') AS end_date
FROM dual
)
CONNECT BY LEVEL <= end_date + 1 - start_date
)
SELECT TO_CHAR ( TRUNC (a_date, 'YEAR') , 'YYYY' ) AS YEAR,
COUNT (*) AS num_days
FROM all_dates
WHERE a_date - TRUNC (a_date, 'IW') < 7
GROUP BY TRUNC (a_date, 'YEAR')
ORDER BY TRUNC (a_date, 'YEAR') ;
I got exact output
Year Number of day
------------------------------
2011 286
2012 366
2013 176
My question is if i use connect by then query execution takes long time as i have millions of records in table and hence i don't want to use connect by clause
connect by clause is creating virtual rows against the particular record.
Any help or suggestion would be greatly appreciated.
From your vague expected results I think you want the number of records between those dates, not the number of days; but it's rather unclear. Since you refer to a table in the question I assume you want something related to the table data, not simply days between two dates which wouldn't depend on a table at all. (I have no idea what the connect by clause reference means though). This should give you that, if it is what you want:
select extract(year from date_field), count(*)
from t42
where date_field >= to_date('01-Jun-2011', 'DD-MON-YYYY')
and date_field < to_date('31-Dec-2013') + interval '1' day
group by extract(year from date_field)
order by extract(year from date_field);
The where clause is as you'd expect between two dates; I've assumed there might be times in your date field (i.e. not all at midnight) and that you want to count all records on the last date in your range. Then it's grouping and counting based on the year for each record.
SQL Fiddle.
If you want the number of days that have records within the range, then you can just vary the count slightly:
select extract(year from date_field), count(distinct trunc(date_field))
...
SQL Fiddle.
you can use the below function to reduce the number of virtual rows by considering only the years in between.You can check the SQLFIDDLE to check the performance.
First consider only the number of days between start date and the year end of that year or
End date if it is in same year
Then consider the years in between from next year of start date to the year before the end date year
Finally consider the number of days from start of end date year to end date
Hence instead of iterating for all the days between start date and end date we need to iterate only the years
WITH all_dates AS
(SELECT (TO_CHAR(START_DATE,'yyyy') + LEVEL - 1) YEARS_BETWEEN,start_date,end_date
FROM
(SELECT TO_DATE ('21/03/2011', 'DD/MM/YYYY') AS start_date ,
TO_DATE ('25/06/2013', 'DD/MM/YYYY') AS end_date
FROM dual
)
CONNECT BY LEVEL <= (TO_CHAR(end_date,'yyyy')) - (TO_CHAR(start_date,'yyyy')-1)
)
SELECT DECODE(TO_CHAR(END_DATE,'yyyy'),YEARS_BETWEEN,END_DATE
,to_date('31-12-'||years_between,'dd-mm-yyyy'))
- DECODE(TO_CHAR(START_DATE,'yyyy'),YEARS_BETWEEN,START_DATE
,to_date('01-01-'||years_between,'dd-mm-yyyy'))+1,years_between
FROM ALL_DATES;
In Oracle you can perform Addition and Substraction to dates like this...
SELECT
TO_DATE('31-Dec-2013','dd-MM-yyyy') - TO_DATE('01-Jun-2011','dd-MM-yyyy')
DAYS FROM DUAL;
it will return day difference between two dates....
select to_date(2011, 'yyyy'), to_date(2012, 'yyyy'), to_date(2013, 'yyyy')
from dual;
TO_DATE(2011,'Y TO_DATE(2012,'Y TO_DATE(2013,'Y
--------------- --------------- ---------------
01-MAY-11 01-MAY-12 01-MAY-13
select to_char(date_field,'yyyy'), count(*)
from your_table
where date_field between to_date('01-Jun-2011', 'DD-MON-YYYY')
and to_date('31-Dec-2013 23:59:59', 'DD-MON-YYYY hh24:mi:ss')
group by to_char(date_field,'yyyy')
order by to_char(date_field,'yyyy');
The time is: (m/d/yyyy) => 2009/01/04
Using this command using datepart(wk,'20090104') I can get the week number (for any given date).
So :
SELECT datepart(wk,'20090101') //1
SELECT datepart(wk,'20090102') //1
SELECT datepart(wk,'20090103') //1
SELECT datepart(wk,'20090104') //2
So far so good.
The problem :
Those 3 first dates are not part of a full week, so I can't put them in a fixed 52-week chart.
Our company needs to see information about each whole week in the 52 weeks of a year. (Each year has 52 whole weeks).
So 20090101 doesn't belong to the first week of 2009 !
It belongs to the previous year (which is irrelevant to my question)
So I need a UDF (I've been searching a lot, and ISOWEEK is not answering my needs) which by a given datetime, will give me the Week Number (week = whole week, so partial weeks aren't considered).
Example :
calcweekNum ('20090101') //52 ...from the last year
calcweekNum ('20090102') //52 ...from the last year
calcweekNum ('20090103') //52 ...from the last year
calcweekNum ('20090104') //1
..
..
calcweekNum ('20090110') //1
calcweekNum ('20090111') //2
calcweekNum ('20090112') //2
...
Here's a different approach. All you need to supply is the year:
DECLARE #year INT = 2009;
DECLARE #start SMALLDATETIME;
SET #start = DATEADD(YEAR, #year-1900, 0);
;WITH n AS
(
SELECT TOP (366) -- in case of leap year
d = DATEADD(DAY, ROW_NUMBER() OVER (ORDER BY name)-1, #start)
FROM sys.all_objects
),
x AS
(
SELECT md = MIN(d) FROM n
WHERE DATEPART(WEEKDAY, d) = 1 -- assuming DATEFIRST is Sunday
),
y(d,wk) AS
(
SELECT n.d, ((DATEPART(DAYOFYEAR, n.d) - DATEDIFF(DAY, #start, x.md)-1)/7) + 1
FROM n CROSS JOIN x
WHERE n.d >= x.md
AND n.d < DATEADD(YEAR, 1, #start)
)
SELECT [date] = d, [week] = wk
FROM y WHERE wk < 53
ORDER BY [date];
Results:
date week
---------- ----
2009-01-04 1
2009-01-05 1
2009-01-06 1
2009-01-07 1
2009-01-08 1
2009-01-09 1
2009-01-10 1
2009-01-11 2
2009-01-12 2
...
2009-12-25 51
2009-12-26 51
2009-12-27 52
2009-12-28 52
2009-12-29 52
2009-12-30 52
2009-12-31 52
Note that week 52 won't necessarily be a full week, and that in some cases (e.g. 2012), the last day or two of the year might fall in week 53, so they're excluded.
An alternative approach is to repeat the MIN expression twice:
DECLARE #year INT = 2009;
DECLARE #start SMALLDATETIME;
SET #start = DATEADD(YEAR, #year-1900, 0);
;WITH n AS
(
SELECT TOP (366) -- in case of leap year
d = DATEADD(DAY, ROW_NUMBER() OVER (ORDER BY name)-1, #start)
FROM sys.all_objects
),
y(d,wk) AS
(
SELECT n.d, ((DATEPART(DAYOFYEAR, n.d) - DATEDIFF(DAY, #start, (SELECT MIN(d)
FROM n WHERE DATEPART(WEEKDAY, d) = 1))-1)/7) + 1
FROM n
WHERE n.d >= (SELECT md = MIN(d) FROM n WHERE DATEPART(WEEKDAY, d) = 1)
AND n.d < DATEADD(YEAR, 1, #start)
)
SELECT [date] = d, [week] = wk
FROM y WHERE wk < 53
ORDER BY d;
Here's a function for you to calculate it on the fly:
CREATE FUNCTION dbo.WholeWeekFromDate (
#Date datetime
)
RETURNS tinyint
AS BEGIN
RETURN (
SELECT DateDiff(Day, DateAdd(Year, DateDiff(Year, 0, CalcDate), 0), CalcDate) / 7 + 1
FROM (SELECT DateAdd(Day, (DateDiff(Day, 0, #Date) + 1) / 7 * 7, 0)) X (CalcDate)
);
END;
I don't recommend you use it, as it may perform badly due to being called once for every row. If you absolutely must have a function to use in real queries, then convert it to an inline function returning a single column and row, and use it as so:
SELECT
OtherColumns,
(SELECT WeekNumber FROM dbo.WholeWeekFromDate(DateColumn)) WeekNumber
FROM
YourTable;
This will allow it to be "inlined" in the execution plan and perform significantly better.
But even better, as others have suggested, is to use a BusinessDate table. Here's a head start on creating one for you:
CREATE TABLE dbo.BusinessDate (
BusinessDate date NOT NULL CONSTRAINT PK_BusinessDate PRIMARY KEY CLUSTERED,
WholeWeekYear smallint NOT NULL
CONSTRAINT CK_BusinessDate_WholeWeekYear_Valid
CHECK (WholeWeekYear BETWEEN 1900 AND 9999),
WholeWeekNumber tinyint NOT NULL
CONSTRAINT CK_BusinessDate_WholeWeekNumber_Valid
CHECK (WholeWeekNumber BETWEEN 1 AND 53),
Holiday bit CONSTRAINT DF_BusinessDate_Holiday DEFAULT (0),
Weekend bit CONSTRAINT DF_BusinessDate_Weekend DEFAULT (0),
BusinessDay AS
(Convert(bit, CASE WHEN Holiday = 0 AND Weekend = 0 THEN 1 ELSE 0 END)) PERSISTED
);
And I'll even populate it from 1900-01-01 through 2617-09-22 (Is that enough for the projected life of your product? And it's only 7.8MB so don't fret over size):
WITH A (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),
B (N) AS (SELECT 1 FROM A F, A A, A L, A C, A O, A N),
C (N) AS (SELECT Row_Number() OVER (ORDER BY (SELECT 1)) FROM B),
Dates AS (
SELECT
N,
DateAdd(Day, N, '18991231') Dte,
DateAdd(Day, N / 7 * 7, '19000101') CalcDate
FROM C
)
INSERT dbo.BusinessDate
SELECT
Dte,
Year(CalcDate),
DateDiff(Day, DateAdd(Year, DateDiff(Year, 0, CalcDate), 0), CalcDate) / 7 + 1,
0,
(N + 6) % 7 / 5 -- calculate weekends
FROM Dates; -- 3-7 seconds or so on my VM server
Then join to the table on the date, and use the WholeWeekNumber column for your output. You might also consider adding a WeekNumberYear because it's going to be a tad difficult to figure out that the 52 of 2009-01-01 really belongs to 2008 without this... a strange data point in there for sure if you don't (laugh).
Example table contents:
BusinessDate WholeWeekYear WholeWeekNumber Holiday Weekend BusinessDay
------------ ------------- --------------- ------- ------- -----------
1/1/2009 2008 52 0 0 1
1/2/2009 2008 52 0 0 1
1/3/2009 2008 52 0 1 0
1/4/2009 2009 1 0 1 0
1/5/2009 2009 1 0 0 1
1/6/2009 2009 1 0 0 1
1/7/2009 2009 1 0 0 1
1/8/2009 2009 1 0 0 1
1/9/2009 2009 1 0 0 1
1/10/2009 2009 1 0 1 0
1/11/2009 2009 2 0 1 0
If you really don't want to use this as a general business date calculation table, you can drop the last 3 columns, otherwise, update the Holiday column to 1 for company holidays.
Note: if you actually make the above table, and your access to it most often uses JOIN or WHERE conditions on a different column than BusinessDate, then make the primary key nonclustered and add a clustered index starting with the alternate column.
Some of the above scripts require SQL 2005 or higher.
It would be relatively easy to setup a custom calendar table with one row for each date of the year in it, and then have other fields that will allow you to rollup however you want. I do this when I have clients using varying calendars, i.e. fiscal years, and it makes the query logic very simple.
Then you just join date-to-date and get the week-number that you want.
date | reporting year | reporting week
-----------|----------------|---------------
2009-01-01 | 2008 | 52
2009-01-02 | 2008 | 52
2009-01-03 | 2008 | 52
2009-01-04 | 2009 | 01
2009-01-05 | 2009 | 01
etc.
and then to use it ( for example to get total sales rollup by your custom weeks, didn't validated my sql):
select reporting_year, reporting_month, sum(sales)
from sales
inner join custom_date_table cdt on cdt.sysdate = sales.sysdate
group by reporting_year, reporting_month
where report_year=2009
DECLARE #StartDate DATE;
SET #StartDate = '20120101';
WITH Calendar AS (
SELECT #StartDate AS DateValue
,DATEPART(DW, #StartDate) AS DayOfWeek
,CASE WHEN DATEPART(DW, #StartDate) = 1 THEN 1 ELSE 0 END AS WeekNumber
UNION ALL
SELECT DATEADD(d, 1, DateValue)
,DATEPART(DW, DATEADD(d, 1, DateValue)) AS DayOfWeek
,CASE WHEN DayOfWeek = 7 THEN WeekNumber + 1 ELSE WeekNumber END
FROM Calendar
WHERE DATEPART(YEAR, DateValue) = DATEPART(YEAR, #StartDate)
)
SELECT DateValue, WeekNumber
FROM Calendar
WHERE WeekNumber BETWEEN 1 AND 52
AND DATEPART(YEAR, DateValue) = DATEPART(YEAR, #StartDate)
OPTION (MAXRECURSION 0);
Don't use a UDF, use a calendar table instead, then you can define week numbers exactly as your company requires and simply query them from the table, which will be much easier and possibly much faster than using a UDF.
A calendar table has numerous uses in SQL (search this site or Google) so you should probably create it anyway.
There is no good answer for this.
A year is NOT 52 weeks long.
It is 52 weeks and one day in normal years, and 52 weeks and two days in leap years.