Thanks you for the correction regarding COUNT(NULL). I found that in T-SQL it is not valid, but I think it works in some other dialects (I think it is valid...

kapil_kk (4/15/2013)

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For the last query:

select COUNT(convert(int,NULL)) from #temp

It will return 0 because when you execute the query:

SELECT CONVERT(int,NULL) it will return NULL and as the return type of COUNT is...

If you are using SSRS 2008 you can use indicators. The link is for a video that demonstrates how to use them:

http://youtu.be/Krz120kooGc