Hi @Maxime_Rocchia,
The function DateMember() understands relative dates. That means you don’t need to parse these values additionally with DateParse(). Additionally, you use the “Weekly” hierarchy in Time dimension in the report rows. But in the calculated measure, you reference the default Time dimension hierarchy. With such a configuration, you won’t retrieve the expected results.
You can either address that with [Time.Weekly].[Day].DateMember or, create a universal approach that will work with all Time dimension hierarchies with [Time].Currenthierarchy.Levels("Day").Datemember('1 month ago')))').
See more details about DateMember() function here - DateMember.
Best,
Roberts // support@eazybi.com