Create New Column containing value based on conditions on date and hour - powerbi

Question

I have a table in my power BI with the following fields :
Preview of the data:
The column "platform" has 3 possible values : application, shop, website
"day" is of type Date
"hour" is of type "Date/Time" (same information as "day" + has the hour)
I added a measure to calculate the conversion_rate (orders/visits):
conversion_rate = DIVIDE(SUM(Table[orders]), SUM(Table[visits]))
Then I calculated for every day the conversion_rate from 7 days ago (to be able to compare them):
conversion_rate_7_j = CALCULATE(Table[conversion_rate],
DATEADD(Table[day],-7,DAY)
)
Now my data looks like this:
What I want to do is calculate the conversion rate from 7 days ago but for the same hour.
However I couldn't find a function that substracts field of type Date/Time while taking in consideration the hour.
A solution I thought of is to calculate orders and visits -7 days same hour separately and then divide them to have the conversion rate -7 days same hour:
orders_7_j_hourly =
VAR h = Table[hour] - 7
VAR p = Table[platform]
Return CALCULATE(
MAX(Table[orders]),
Table,
Table[hour] = h,
Table[platform] = p
)
Since my data is grouped by hour (Date/Time) and platform,
And since sometimes for a certain hour I have values for the platform = "application" but not "shop",
My function did not work especially that I am using MAX, this associated the number of orders to the wrong platform.
Can you please help ?
Sample data : https://ufile.io/y1blqgqn

Answer 1

Datetime values are stored in units of days. Thus you can simply shift hour by 7 in your measure.
conversion_rate prev_week =
VAR CurrHour = SELECTEDVALUE ( Table1[hour] )
RETURN
CALCULATE (
[conversion_rate],
ALL ( Table1[day] ),
Table1[hour] = CurrHour - 7
)
Sample results:

Answer 2

Did you try to use HOUR function ??
conversion_rate_7_hour = CALCULATE( [conversion_rate],
FILTER( ALL(Table),
SELECTEDVALUE(Table[day]) - 7 = Table[day]
&& HOUR(SELECTEDVALUE(Table[hour]) - 7) = HOUR( Table[hour])
))
When we put Table[hour] to visualization it should work.
Ps. best pratice => if your refer to measures in your calculations,do not include the table prefix

Answer 3

You can create an additional column called hour in your dataset
Once you have that, you bring the hours in the viz, the following measure can give you what you want
convRate-7 = CALCULATE([convRate],DATEADD('Table'[day],-7,DAY))