How do I force specific rows in a query

I am creating a Web Intelligence report in BusinessObjects and I am trying to find a count of items raised in a each month and show them by priority. I am looking to have an output of the following:

+----+-----+-----+-----+
|    | Jan | Feb | Mar |
+----+-----+-----+-----+
| P1 |   1 |   2 |   1 |
| P2 |  34 |  56 |  34 |
| P3 |  56 |  34 |  87 |
| P4 |  67 |  67 |  34 |
+----+-----+-----+-----+

I have created a query that returns the Id, Month & Priority columns of the data that I want to report on. In the report, I have created a grid which have the Months as the column headers, the Priority as the Row headers and a formula below as the value cells:

=Count([Id])

This gives me a grid that looks exactly like the one above... However, when I run it against this year so far, there have not been any items with the P1 flag set against them so that row does not show at all!

How can I force that row to show in the grid but with all zeroes if there are no items?

Thanks

Solution

you have to create a separate query with just Priority, merge queries by Priority and replace column [Query1].[Priority] with the merged dimension [Priority].