SSRS Matrix not showing all the entry for a Column Groups

Question

I created a Matrix in my SSRS report and for some reason if the COLUMN GROUP has more than one
entry it only shows the first one and not the second or consequent entries.
I opened a question in SO and here is the link:
http://stackoverflow.com/questions/23248421/how-to-add-column-in-a-ssrs-table-based-on-criteria
All help is appreciated.

Answer 1

Hi SiKni8,
According to your description, you have a matrix report. If a user has more than one start date and end date, you want to put all those start dates and end dates into one single row for this user. Right?
In Reporting Service, for all data fields textbox appearing at intersection of rows and columns, the matrix will use Sum aggregation function by default. If the data can’t be calculated by aggregation function, it will return the first one of records. This
is the reason why you only get the first start date and end date for each user. In your scenario, it is impossible to append more columns at the end of the matrix without setting column group. And we can never append columns dynamically based on the numbers
of the records. So for your requirement, we find a workaround which we think is the most related to the answer you want. We use custom code to get both StartDate and EndDate, then return them as string. After that we append those strings and put the whole
string into a cell. Your case has been tested in our local environment. Here are steps and screenshots for your reference:
Put the custom code below into your report:
Dim Num As String = ""
Dim tempstr As String = ""
Function AggregateString(Title as String, StartDate as String, EndDate as String) 
If Title = Num Then
   tempstr = tempstr + "(" +StartDate+" , "+EndDate+")  "
Else
  tempstr=""
  Num = Title
  tempstr =tempstr+"("+StartDate+" , "+EndDate+")  "
End If 
Return tempStr 
End Function
In our sample report, we created a matrix based on your description. It looks like below:
In textbox next to [Title], put the expression below into it:
=runningvalue(Code.AggregateString(Fields!Title.Value,Fields!StartDate.Value,Fields!EndDate.Value),Last,"Title")
Ps: In our report, we set the type of date as string when creating table and dataset. If your date type is different, use Cstr() function and convert it into string.
Save and preview. The result looks like below:
Reference:
Matrices (Report Builder and SSRS)
RunningValue Function (Report Builder and SSRS)
If you have any question, please feel free to ask.
Best Regards,
Simon Hou