Issue with presentation variables, dashboard prompt and filter

Question

Dear Guru's,
I have a question about constraining a request with presentation variable set by a dashboard prompt. I have a dashboard prompt, that stores its value in a presentation variable . The prompt is about region. When the dashboard opens, the default of the prompt is all choices and it needs to show my reports with "All Choices". I've created the following filter on my two reports on the dashboard:
"Dim Student"."Region" = '@{variables.GILLES}'
or '@{variables.GILLES}' IS NULL
One report is just the column "Dim Student"."Region" (to see if it works) and with this report the above filter works just fine. When nothing is prompted it shows "All Choices" when a choice is made the report responds accordingly.
BUT
The second report on my dash with the same region column, but extended with some time dimension columns and a measure gives an error which I'm not able to solve.
+State: HY000. Code: 10058. [NQODBC] [SQL_STATE: HY000] [nQSError: 10058] A general error has occurred. [nQSError: 14023] None of the fact sources for ToDate(# Feitelijke Instroom:[DAggr(Feit Instroom en Uitstroom Opleidingen.# Feitelijke Instroom by [ Dim Tijd.Maand Omschrijving, Dim Tijd.Maand Nummer, Dim Tijd.Jaar, Dim Kwalificatie.Kwalificatie Niveau, Dim Leerling.RCBREGIO Regio] )], [Level JAAR]) are compatible with the detail filter [Dim Tijd.Maand Nummer = 3, Dim Tijd.Jaar = 2010].+
+(HY000)SQL Issued: SELECT "Dim Tijd".Jaar saw_0, "Dim Tijd"."Maand Nummer" saw_1, "Dim Tijd"."Maand Omschrijving" saw_2, "Dim Kwalificatie"."Kwalificatie Niveau" saw_3, "Dim Leerling"."RCBREGIO Regio" saw_4, "Feit Instroom en Uitstroom Opleidingen"."# Feitelijke Instroom Cumulatief" saw_5, REPORT_SUM(saw_5 BY saw_0, saw_1, saw_2) FROM repos_x WHERE ("Dim Tijd".Jaar = 2010) AND ("Dim Tijd"."Maand Nummer" = 3) AND (("Dim Leerling"."RCBREGIO Regio" = 'Noord-Oost') OR ('Noord-Oost' IS NULL)) ORDER BY saw_0, saw_1, saw_2, saw_3, saw_4+
While the exact same report but without the "or '@{variables.GILLES}' IS NULL" doesn't throw any errors but doesn't show the "all choices" by default.
The ultimate goal to achieve is to build a dashboard with several reports from several subject areas with one single prompt that opens default with "all choices" and constrains the reports accordingly.
Any help is highly appreciated.
Kind Regards,
Gilles

Answer 1

Phani,
I know "All Choices" is a special value and that it doesn't represent NULL. My filter construction seems to work fine.
My filter condition:
"Dim Student"."Region" = '@{variables.GILLES}'
or '@{variables.GILLES}' IS NULL
When it's set by the prompt it filters the request accordingly (first condition evaluates to true), when it's not set the second condition evaluates to true and shows all the results (or it's not filtered).
The problem is that it doesn't work when time dimensions are combined with this filter. Then it throws the error mentioned in the first post.
By the way: your suggested solution doesn't work.