expression help

[Anonymous]

I Have two tables one is user another one is seesionlog

in session log  identyfy user name colume is present

in user   identify username column present

both have relation

now i need to get the  username value that is not present in the sessionlog table

[Gysbert_Wassenaar]

Create a straight table and add username as dimension and as expression count({<username={'=count(sessionid)=0'}>}1). Replace username with the name of your username field and sessionid with a field name from your session log table. You can hide the expression if you want.