hi Gennaro,
you asked in the original post how to have a column for Open Tickets. here is how to do that:
A) if you created a formula with this syntax (and place the formula on the Details section)
{CallLog.CallStatus} <> "Closed"
then you will get a TRUE output for all of the open tickets. this will indicate line by line any tickets that are open by displaying TRUE.
B) you could also change the formula to the following if you want to display Closed or Open.
if {CallLog.CallStatus} <> "Closed" then "Open"
C) if you then need to count open tickets,
1) create another formula with syntax like
if {CallLog.CallStatus} <> "Closed" then 1
2) put this formula on your report
3) right click on the formula and choose Insert Summary and then choose sum...if you've got a group on the analyst, then choose to have the summary inserted on the group level to get the count of open tickets per analyst.
-jamie