function week() can deliver different results depending on the "FirstWeekDay" setting

Description:

Please note that the function week() can deliver different results depending on the setting for the "FirstWeekDay".

Example 1:

1) Open the Data Load Editor in Qlik Sense and make sure that you have the setting "SET FirstWeekDay=0;"
2) Add the following code: "let test = week(makedate(2019,5,12));"
3) Check the output of the variable "test" --> it should be 19.

Example 2:

1) Open the Data Load Editor in Qlik Sense and make sure that you have the setting "SET FirstWeekDay=6;"
2) Add the following code: "let test = week(makedate(2019,5,12));"
3) Check the output of the variable "test" --> it should be 20.

 

Cause:

This behavior is working as designed.

Please note that the 12th of May (makedate(2019,5,12)) is a Sunday and depending if you FirstWeekDay=6 or FirstWeekDay=0 you define the first day of the week as Sunday or Monday which leads to the provided results 20 or 19.

For more information please check the help page: https://help.qlik.com/en-US/sense/April2019/Subsystems/Hub/Content/Sense_Hub/Scripting/NumberInterpretationVariables/FirstWeekDay.htm