Let's say that you have a column

named some_id in an outer-joined table that will return a value if a record exists

and will return null if a record doesn't exist...

1. Add an image item to a table cell.

2. Add two embedded images to the

   report; a check mark and a blank white square the same size. Let's call the image

   files Check.png and Blank.png (or JPG, GIF, BMP, TIF, etc.)

3. For the Value property of the

   image report item, use an expression like:

   =IIF(IsNothing(Fields!some_id.Value), "Blank", "Check")

In the table or group footer,

use a COUNT function with the same field: =COUNT(Fields!some_id.Value)

This will only count the existing values.

Weblog by Paul Turley and SQL Server BI Blog.