Sum function in qlik

[#1]

Hello every body! for example  i have this data.

now i want to take data this day and data of 7 days ago. what can i do with qlik sense.

if i choose date in filter pane is 07/01/2015 i have report like this:

[Gysbert_Wassenaar]

Perhaps like this =sum({<DATE={<$(=Date(Only(DATE)-7,'MM/DD/YYYY'))>}>}AMOUMT)

[Anonymous]

Hi

if you would like to have all the sum from last 7 days

in Expression :

=Sum({<DATE = {">=$(=Date(Today()-6,'MM/DD/YYYY'))<=$(=Date(Today(),'MM/DD/YYYY'))"}} Amount)

if you would like to have Only on  7 days ago.

=Sum({<DATE = {"$(=Date(Today()-6,'MM/DD/YYYY'))"}} Amount)

[#4]

so If 2 have 2 table: i need to calculated 2 amounts, amount_1 + amount_2. Which calculation can i use? please help me.

Thank so much