sum for the period

[AIShatiLove]

Hi, experts
Need to sum money for period  where [date of sales]  between [date 0f sales]-6 months and [date of sales]+ 7 days 
how i can write this condition in table

[Or]

This is an impossible situation: [date of sales] can never be [date of sales] minus 6 months - it is by definition [date of sales]..?

[AIShatiLove]

Ok , how then to set the period ?
Is using filter to set this period  good idea ?

[Or]

You can use a separate field to filter this, yes. I'm not sure why you wouldn't simply ask the user to select the range they want, but if they select a single date and you want the range specific above, you can do this in set analysis. See this thread for example syntax: https://community.qlik.com/t5/QlikView-App-Dev/Date-range-in-set-analysis/m-p/965088