Thanks for the reply. I got the difference between these tables.
I am checking DOC ID : 295206.1 . In that in Step 1, they used
v$session b, v$process c, apps.fnd_user d tables to get the count of concurrent_users
But in step 4, icx_sessions was used to find number of users on system.
The difference between Step 1 &4 is,
Step 1 SQL gives only Active sessions who are on the system right now (or if there is row v$session or v$process for assocaited entry in fnd_logins table) and other one gives the
commutative number of users who are/ were logged into system in last one hour , one day or so.
Please correct me if i am wrong .
You are correct.