I have a report where I capture patient information, some of which is stored in the patient table and some of which is stored in the observations table. Taking date of birth as my example, if I count all the records for which the DOB has been supplied, I get significantly more than the total number of patients, because of the join to the observations table. How do I evaluate the running total only once for each group? Edit: sample data at http://sqlfiddle.com/#!3/27b91/1/0.

Hi There You just need to create a group report on the filed which are unique inside your data and then take a distinct count of your group. =CountDistinct(Fields!pid.Value) I am putting some screenshot for your help. Many thanks Syed Qazafi Anjum Please click "Mark as Answer" if this resolves your problem or "Vote as Helpful" if you find it helpful.

I didn't ask how many patients I had, I asked how many patients supplied a date of birth.

Hi There Please change the expression =CountDistinct(Fields!dateOfBirth.Value) =CountDistinct(Fields!dateOfBirth.Value) The result will be 2. is this what you after Please update many thanks Syed

...which will count how many distinct dates of birth there are, not how many distinct patients supplied a date of birth. If you have twins, you'll count them once with the above code, not twice.

I think I figured it out -- this seems to work as I expected it to. =RunningValue(Iif(Not IsNothing(Fields!DATEOFBIRTH.Value) , Fields!PATIENTID.Value , Nothing) , CountDistinct , Nothing )