How to make zero tablix data rows appear?

I am developing an SSRS 2008 report开发者_JAVA百科. I created a tablix, however, when I view this report one of the rows has zero entries. This row is not showing in the output. How can I make it show regardless of values so that it will just show "0" otherwise?

This was the expression I used for it:

=iif(CountDistinct(Fields!Client.Value)=0 or 
isnothing(countdistinct(Fields!Client.Value)),0,
CountDistinct(Fields!Client.Value))

And I have tried grouping on different fields and also filtering on another field, but none of these make it appear when there is no data.

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I think that the best you can do is ensuring that the dataset you are using has the record you want, even if it is null. For example, if you are grouping months, and you want all 12 months to appear in your tablix, then you need to make those months to exist in your dataset even if they have null values for all the other columns.