calculating the weekly hours worked and excluding the weekends using SQL - sql

Question

I have table like shown below and i would like to capture all 5 week days in every week whether the employee worked or not. If employee only worked 3 days, then i want to show the hours for the 3 days that he/she worked and assign 0 for the 2 missing days :
UID DT HOURS_WORKED
Mike 07/4/16 5
Mike 07/5/16 8
Mike 07/7/16 4
here is the desired results for this scenario
UID DT HOURS_WORKED
Mike 07/4/16 5
Mike 07/5/16 8
Mike 06/6/16 0
Mike 07/7/16 4
Mike 07/8/16 0
so i want to put 0 when they skipped work for that day. I don't want to show weekends. Thanks for your help
select UID, DT, HOURS_WORKED from my table

Answer 1

I enhanced #vkp 's answer to make it more generic, ( if you are really picky we need to handle the edge cases where some days of the 1st week or last week can fall into different years )
Over here I have added the ability to change the first day of the week using the Datefirst setting . more on Datefirst MSDN : https://msdn.microsoft.com/en-us/library/ms181598.aspx
/* Setup Test Data
Drop Table #T1
Create Table #T1 ( UID Varchar(10), Dt Date, Hrs int )
insert into #T1 Values
( 'Mike' , GetDate() , 8 ) , -- Sat 07/23
( 'Mike' , GetDate()-1 , 8 ) ,
( 'Mike' , GetDate()-2 , 8 ) ,
( 'Mike' , GetDate()+3 , 8 ) -- Tue 07/26
( 'John' , GetDate() , 8 ) , -- Sat 07/23
( 'John' , GetDate()-1 , 8 ) ,
( 'John' , GetDate()-2 , 8 ) ,
( 'John' , GetDate()+3 , 8 )
insert into #T1 Values
( 'Mike' , GetDate() - 206 , 8 ) , --- One Date for Last Year 12/30 to Test Edge Case
-- select * , DatePart( WEEK, Dt) from #T1
*/
-- Create a Helper TV Function To get Dates for a Given Week in a Year
ALTER FUNCTION GetDates
(
#WK int ,
#yr varchar(5) = ''
)
RETURNS
#Table_Var TABLE
(
DD int,
Dt Date,
Wk int
)
AS
BEGIN
IF #yr = '' SET #yr = YEAR(Getdate()) -- If Year is Blank then Default to current year
Declare #LastDateOfYr Date = RTRIM(#YR)+'-12-31' -- Last Day of the year
Declare #LastDayOfYr Int = CAST(Datename(dy, #LastDateOfYr ) as int) -- No.of Days in the Year to Handle Leap Yrs
;WITH Dates as
(
-- SELECT 0 as DD , DATEADD(D, 0, #yr ) as Dt , DatePart( WEEK, DATEADD(D, 0 , #yr )) as Wk
SELECT Datepart( DAYOFYEAR,DateAdd(D, (#WK-2)*7, #yr) ) as DD , DATEADD(D, (#WK-2)*7, #yr ) as Dt , #WK-2 as Wk -- Initial values for the Recursive CTE.
UNION ALL
SELECT Dates.DD+1 as DD , DATEADD(D, Dates.DD, #yr ) , DatePart( WEEK,DATEADD(D, Dates.DD, #yr )) from Dates where Dates.DD <= #LastDayOfYr
AND Wk <= #WK + 1 -- Terminator for Recursion
)
INSERT INTO #Table_Var
SELECT
DD ,
Dt ,
Wk
FROM Dates as A
WHERE A.Wk = #WK
OPTION (MAXRECURSION 21) -- At any point we dont use CTE For more than 3 Weeks (one week actually). If the CTE is changed by using the commented out Initializer inside the CTE Above then this number has to change accordingly
RETURN
END
GO
Query :
SET DATEFIRST 1 -- Make Monday as First Day of Week. The default is Sunday.
Select B.* , A.* , ISNULL(T.Hrs,0) Hours_Worked
FROM
( SELECT Distinct UID,
DatePart( WEEK, Dt) as WK ,
DatePart( YEAR, Dt) as Yr
FROM #T1
) A
CROSS APPLY dbo.GetDates(A.WK, A.Yr ) B -- Helper Function Used to apply
LEFT OUTER JOIN #T1 T ON B.Dt = T.Dt

Answer 2

Construct a dates cte which will have all the dates in a week and perform an outer join on this table to show 0 when the employee doesn't work on a given weekday.
with x as (select cast('2016-07-01' as date) dt
union all
select dateadd(dd,1,dt) from x where dt < '2016-07-31')
select e.uid, t.dt, coalesce(e.hours_worked,0) hours_worked
from (select * from x where datepart(dw,dt) between 2 and 6) t
left join emp_table e on e.dt = t.dt