Week return different values

[waszcma1]

Could anyone explain me this behavior? Today() = 19.02.2021

[MayilVahanan]

Hi @waszcma1 

In week, we can't assign the date format. Generally, 2nd parameter of Week in Qlik takes the firstweekday.

FYR:

https://help.qlik.com/en-US/sense/November2020/Subsystems/Hub/Content/Sense_Hub/Scripting/DateAndTim...

[waszcma1]

Hi, I know that syntax with week( today(),'DD-MM-YYYY') is wrong.

I have discover this in some apps handover to me and noticed that this is have a huge impact of indexing of qvd files where this week calculation is used in naming conventions.  i.e.: store table into file_$(vWeek)_$(vYear).qvd(qvd);

The most odd thing is that
- this syntax week( today(),'DD-MM-YYYY') is not returning any error,
- it is returning different value for 15-17.02.2021. value is 8
- while on 18-19.02.2021 value is 9

I have discovered this when I have been asked to force reload and loading app referring to load * file_$(vWeek)_$(vYear).qvd(qvd) failed, I have debug variables and noticed that on Friday  19.02.2021

application was trying load the file with the name file_9_2021.qvd(qvd) 

I think this is a Qlik Sense bug 

[waszcma1]

week(today()) | = 15 | 16.04.2021
week(today()),'DDMMYYYY') | = 17  | 16.04.2021
week(today()-1,'DDMMYYYY') | = 17 | 15.04.2021
week(today()-2,'DDMMYYYY') | = 16 | 14.04.2021
week(today()-3,'DDMMYYYY') | = 16 | 13.04.2021
week(today()-4,'DDMMYYYY') | = 16 | 12.04.2021

Can someone who is more advanced  than me explain me why the syntax is working but showing wrong week number? 

The interesting behaviur is that week number is +2 for Friday and Thursday but +1 for Mon-Wed
Is it kind of managing BrokenWeeks ? 

I have found this in one of my client and have no idea why it was used in such way for indexing week snapshots ,do you have any idea? 
I think this is really bad approach as the manual reload on Friday or Thursday could casue the issue with generating snapshot file under wrong week number. 

[waszcma1]

and some more examples:

[waszcma1]

Can anyone explain me why week() function is behaving like this with used 'DDMMYYYY' ?

it is becouse of global settings?

SET FirstWeekDay=0;
SET BrokenWeeks=0;
SET ReferenceDay=4;
SET FirstMonthOfYear=1;

[mikaelsc · Accepted solution]

as @MayilVahanan mentionned, you're using the week() function with a wrong parameter

using 'DD MM YYYY' as second parameter is just as useful as using 'Mikael' as second parameter.

it expects the "first_week_day" 

maybe qlik could/should return an empty or null or other error value, but at the basis, you're using a wrong parameter value... 

if you want to store qvd's with week info, maybe use something like this: 

date(weekstart(today()),'YYYY-MM-DD') 

(that should remove the "W1, W53, issues that may appear around New Year...) 

[waszcma1]

Thanks for putting more lights on this 🙂