Get weekStart and weekEnd dynamically? - sql

Question

I have spent so much time trying to figure out how this can be done but could not do it. So please help me out.
I have this data:
ID employee_id worked_date start_time finish_time
1 1 2013-09-25 09:00:00 17:30:00
2 1 2013-09-26 07:00:00 17:00:00
8 1 2013-10-01 09:00:00 17:00:00
9 1 2013-10-04 09:00:00 17:00:00
12 1 2013-10-07 09:00:00 17:00:00
13 1 2013-10-10 09:00:00 17:00:00
14 1 2013-10-11 09:00:00 17:00:00
My first day of the week is Wednesday. The base date is 2013-09-25 which is Wednesday. I need to be able to get the weekStart and weekEnd dynamically. For example, based on the data I have above, there are three weeks between 2013-09-25 to 2013-10-11. I order my data with the latest worked_date first. If the user requested for week3, then the weekStart should be 2013-09-25 and weekEnd should be 2013-10-01. If the user requested for week2, then the weekStart should be 2013-10-02 to 2013-10-08 and so on.
The parameter week will be passed dynamically. Thanks for your help.
Here is the result I want to achieve when the requested week is 3:
ID employee_id worked_date start_time finish_time weekStart weekEnd
1 1 2013-09-25 09:00:00 17:30:00 2013-09-25 2013-10-01
2 1 2013-09-26 07:00:00 17:00:00 2013-09-25 2013-10-01
8 1 2013-10-01 09:00:00 17:00:00 2013-09-25 2013-10-01
Using this query will give me the weekStart and weekEnd for each record
SELECT *, dateadd(week, datediff(day,'20000105',worked_date) / 7, '20000105') AS WeekStart ,
dateadd(week, datediff(day,'20000105',worked_date) / 7, '20000105') + 6 AS WeekEnd
FROM Timesheet
But I do not want this. I want only a particular week that the user requested.

Answer 1

It sounds like you might need a calendar table.
create table calendar (
calendarId int identity(1,1) primary key,
year int,
month int,
week int,
startDate date,
endDate date)
then you could say 'give me all the records for week 2'
declare #week int = 2
declare #year int = 2013
;with employeeCalendar as (
select
employee.employeeid
,startDate
,endDate
from
employee
cross apply
calendar
where
calendar.week = #week )
select
employeeCalendar.EmployeeId
,employeeShift.[date]
,start_time
,finish_time
,startDate
,endDate
from
employeeCalendar
left join
employeeShift
on employeeShift.employeeid = employeeCalendar.employeeid
and employeeShift.worked_date
between employeeCalendar.startDate and employeeCalendar.endDate
You could populate that table with a query like this:
;with calendarCte as (
select
1 as week
,convert(date,'2013-09-25') as startDate
,convert(date,'2013-10-01') as endDate
union all
select
week + 1
,dateadd(week,1,startDate)
,dateadd(week,1,endDate)
from
calendarCte
where
calendarCte.startDate < convert(date,'2043-09-25') )
insert into calendar( [year],[month],[week],startdate,stopdate)
select
datepart(year,startDate) as [year]
,datepart(month,startDate) as [month]
,week as [week]
,startDate
,endDate
from calendarCte option (maxrecursion 0)

Answer 2

You said you are looking for a stored procedure. Are you looking for something like this?
CREATE PROCEDURE ProcedureName #week int AS
SELECT * FROM Timesheet
WHERE worked_date >= dateadd(week, #week, '2013-09-25')
AND worked_date < dateadd(day,7,dateadd(week, #week, '2013-09-25'))
If you want your weekStart and weekEnd you could add them in to the SELECT as you did before.
If you want this in descending order from the current week backwards you could write it as follows.
CREATE PROCEDURE ProcedureName #week int AS
SELECT * FROM Timesheet
WHERE worked_date >= dateadd(week, -#week, '2013-10-16')
AND worked_date < dateadd(day,7,dateadd(week, -#week, '2013-10-16'))
You could also parameterize the Date you are passing into the stored procedure as the current week will always be changing.