HELP REQUIRED ON HOW TO AVOID 'IF ELSE' BY USING CTE

Question

Hi
I've written a script (snippet below) that returns the correct results but I'd like to use a CTE instead as I would like to avoid 'IF ELSE' and also so I can query the results later in the procedure.
Any help would be greatly appreciated.
L
/*ReportingDate variable for testing*/
DECLARE @ReportingDate date = '13-apr-14'
DECLARE @IsWeek1 int
DECLARE @IsWeek53 int
SELECT @IsWeek53 = CASE WHEN ReportingWeekOfYear = 53 THEN 1 ELSE 0 END
FROM d_Date
WHERE DateValue = CAST(DATEADD(dd,-1,@ReportingDate) as date)
/*LAST YEAR*/
BEGIN
IF @IsWeek53 = 1 --If the @ReportingDate falls in Week 53 generate LY's Week 52 equivalent
SELECT a.DateValue OneDayAgo_LY
,DayNameFull
,a.ReportingDayOfWeek
,a.ReportingWeekOfYearName
,a.ReportingMonthOfYearName
,a.ReportingYear_int
,a.ReportingWeekOfMonthName
FROM d_Date a
JOIN (SELECT ReportingYear_int, ReportingWeekOfYear, ReportingDayOfWeek FROM d_Date WHERE DateValue = CAST(DATEADD(dd,-1,@ReportingDate) as date)) b
ON a.ReportingYear_int = b.ReportingYear_int - 1
AND a.ReportingWeekOfYear = b.ReportingWeekOfYear - 1
AND a.ReportingDayOfWeek = b.ReportingDayOfWeek
ELSE
SELECT a.DateValue OneDayAgo_LY
,DayNameFull
,a.ReportingDayOfWeek
,a.ReportingWeekOfYearName
,a.ReportingMonthOfYearName
,a.ReportingYear_int
,a.ReportingWeekOfMonthName
FROM d_Date a
JOIN (SELECT ReportingYear_int, ReportingWeekOfYear, ReportingDayOfWeek FROM d_Date WHERE DateValue = CAST(DATEADD(dd,-1,@ReportingDate) as date)) b
ON a.ReportingYear_int = b.ReportingYear_int - 1
AND a.ReportingWeekOfYear = b.ReportingWeekOfYear
AND a.ReportingDayOfWeek = b.ReportingDayOfWeek
END

Answer 1

Why do you need CTE?
Isnt this enough?
DECLARE @ReportingDate date = '13-apr-14'
/*LAST YEAR*/
SELECT a.DateValue OneDayAgo_LY
,DayNameFull
,a.ReportingDayOfWeek
,a.ReportingWeekOfYearName
,a.ReportingMonthOfYearName
,a.ReportingYear_int
,a.ReportingWeekOfMonthName
FROM d_Date a
JOIN (SELECT ReportingYear_int, ReportingWeekOfYear, ReportingDayOfWeek FROM d_Date WHERE DateValue = CAST(DATEADD(dd,-1,@ReportingDate) as date)) b
ON a.ReportingYear_int = b.ReportingYear_int - 1
AND a.ReportingWeekOfYear = b.ReportingWeekOfYear - CASE WHEN ReportingWeekOfYear = 53 THEN 1 ELSE 0 END
AND a.ReportingDayOfWeek = b.ReportingDayOfWeekWHERE DateValue = CAST(DATEADD(dd,-1,@ReportingDate) as date)
Please Mark This As Answer if it helps to solve the issue Visakh ---------------------------- http://visakhm.blogspot.com/ https://www.facebook.com/VmBlogs