Subtotal issue when subtotaling on a calc field built using CASE function

Question

Okay, I hpe I can explain this well. May be possible that this is something cannot handle in Discoverer. I am using Discoverer Plus to develop a new workbook - cross project expenditure inquiry. A requirement is to not allow a worksheet user to see labor cost (since possible to figure out someone's salary) amount unless they are allowed to view labor cost. I have a function that returns a Y/N value that tells me if they can view labor cost. That works out just fine. So what I am doing is taking my database cost column (which is defined as Number(22,5) in the Oracle table. I create a new calculated column, basically like this -
CASE WHEN expenditure type <> LABOR THEN cost WHEN view labor cost = 'Y' THEN cost ELSE NULL END.
That calculated column is working just fine. I am seeing my desired results in that column. Okay so far.
Next, the users want subtotals by project organization and project. So I created a new total. When I did that, my subtotal row amount is blank.
Okay, I have seen this happen with NULLS before. Like in the gl_je_lines tables, where the accounted_Dr and accounted_Cr may be null, and have to do a NVL function to convert the null to 0 and allow me to subtotal on the column in a Discoverer workbook.
So I tried creating a second calculation -
NVL(Cost,0)
So I return the cost if not null, otherwise I return 0. Second calc column results look okay.
Now I did a subtotal on the second calculation. Oops. Wrong result. Amount is shown as 0.
For grins, I went back to my CASE statement on my first calculation and changed the ELSE condtion from NULL to 0. When I did that, the subtotal on that column changes from a blank (Null) value to a 0 value. Well, better, but still just like my second calculation subtotal.
Obviously the users have the option to export to Excel and subtotal in Excel.
Does anyone know of a way to get a good subtotal in this kind of situation, where I am attempting to subtotal on a calculated field that is built on a CASE function? Or am I out of luck when it comes to Discoverer?
John Dickey

Answer 1

Okay, I did find a workaround, though I do not understand why the workaround works, but why the way I first tried to get a subtotal did not work. What I did is that I had to go to Discoverer Administrator. I picked my folder and did an Insert/Item. I created my new item building the same CASE statement that I used in my worksheet to create a new calculation. I then closed Discoverer Plus and reopened Discoverer Plus. Opened my worksheet. Edited the worksheet and brought in my new (derived) item from my folder. Then I created my subtotals for this secured cost amount. Voila. I get a number now, and the subtotal amount appears to be correct (still testing/verifying, but looks okay so far). So I deleted my subtotals on my calculated column and then deleted the calculation, to get that stuff out of the report. Sure would be nice if there was documentation in the Discoverer manuals about this.
John Dickey