Accessing Previous records!

[habibsyed01]

Hello Everyone!

Scenario

Here is my situation. I have a table/view that records every transaction. In Power BI I have aggregated the table to show summary for each day for last 8 days. I have a requirement to compute the growth in total consultations by comparing the total consultation for a specific date for example Sep 7, 2018 to the total consultation on the date which was 1 week before the specific date i.e., Aug 31, 2018

The growth is calculated by the formula:
(Total consultations for current date - Total consultations for Last weeks date)/(Total consultation for last weekdate)

Problem

I can access the current total consultations as it is the current record. But having a hard time trying to access the last week consultations. 

What I am looking for is something to let me access the records based on a date condition.

Something that would 

1. take current record date - 7 days,

2. use this date as a filter to apply on whole table,

3, get the records that match this date

4. and sum the total consultation for this records.

Now number 2  and 3 are the issue that I am unable to solve. I would apprecitate if anyone can point me in the right direction.

[v-yuezhe-msft]

@habibsyed01,

I make a test using the sample table below. And create the following columns.

Index = RANKX(FILTER(Table3,Table3[Date]<EARLIER(Table3[Date])),Table3[Date],,ASC,Dense)

last 7 days value = CALCULATE(SUM(Table3[Value]),FILTER(Table3,Table3[Index]=EARLIER(Table3[Index])-7))

If the above DAX don't help, please share sample data of your table that can be copied and pasted here. Also post expected result in the forum.

Regards,
Lydia