I got it to work, not sure it’s 100% correct in the most efficient way of doing this.
You’ll need a date table (i.e. singular dates) to use the DATEADD function, to do this add a new table using this DAX: DateTable = CALENDAR(min(calctable[collectiondt]),max(calctable[collectiondt]))
I then created a duplicate of the [collecitondt] column, but without time: LINKDATE = DATE(calctable[collectiondt].[Year],calctable[collectiondt].[MonthNo],calctable[collectiondt].[Day]) and created a relationship to the Date column in the date table.
I then added a column to the DateTable using this: Last 7 Day Sum = Last 7 Day Sum = CALCULATE(sum(calctable[result]),DATESBETWEEN(DateTable[Date],DATEADD(DateTable[Date],-7,DAY),DateTable[Date])).
In your display table you’ll need to use the Date from DateTable, but you can add collectiondt in there too, but you’ll see duplicated numbers of the last 7 day sum per time entry.
Hope this helps.
RM.