Get Next Value within Row Groups in SSRS - sql

Question

I have a problem I'm trying to solve with getting the NextRow value but only within the specific RowGroup.
Here's what I'm trying to do:
if Fields!Interventions.Value is not blank and nextrow(Fields!DateOccurred.Value) within the group is within 4 hours then Y else N
and another column:
if Fields!Interventions.Value is not blank compare currentrow(Fields!DateOccurred.Value) to nextrow(Fields!DateOccurred.Value) and display the differences in hours
But I'm stuck as to how i could do this expression from within SSRS.
I saw the following question:
Get previous,current and Next Record in ssrs report in a page
but the issue with this one is that it doesn't work with Row Groups in SSRS.
Upon further advise, it appears as this isn't possible to do in SSRS, but would be possible in the query itself.
This is the query I'm working with:
SELECT
ROW_NUMBER() OVER(PARTITION BY R.PatientID, PL.ChartLocationID ORDER BY P.DateOccurred ASC) As Row#,
R.NameFirst,
R.NameLast,
P.DateOccurred,
CASE P.Interventions
WHEN 1 Then 'Regular Analgesia'
When 2 Then 'Heat Pack'
When 4 Then 'Cold Pack'
When 8 Then 'Massage'
When 16 Then 'Exercise'
When 32 Then 'Other'
END as Interventions
FROM
ChartEntry P
LEFT JOIN ChartLocation PL on
P.ChartLocationId = PL.ChartLocationId
Inner Join Resident R on
PL.ResidentID = R.PatientID
where
P.DateDeleted is null and
P.DateOccurred >= '01 Jul 2017' and
P.DateOccurred < '01 Aug 2017'
Is it possible to achieve?
Here is some sample data showing the results for the extra two columns:

Answer 1

Easiest and better way is to use LAG/LEAD in your SQL to figure this out.

Answer 2

You can do this in SSRS:
Set your detail value to Previous(Fields!DateOccurred.Value) and the detail row visibility to = RowNumber("yourgroup") = 1 which will hide the first row.
Use one row on the group total, in order to display the last value by setting its value to =Last(Fields!DateOccurred.Value)
The date difference expression check for the detail will be
=Iif(
NOT(Fields!Interventions.Value Is Nothing) AND
DateDiff("h", Previous(Fields!DateOccurred.Value),Fields!DateOccurred.Value)>=4,
"Y",
"N"
)
and for the last line
=Iif(
NOT(Fields!Interventions.Value Is Nothing) AND
DateDiff("h", Last(Fields!DateOccurred.Value),Now())>=4,
"Y",
"N"
)
In the images below, the red line will be hidden with the visibility condition.
Your report will contain only the expected date column, I include the current row date for demonstration.