How to know user detail

Dear Expert,

There are many user login with same ID,for every user there are max two session , My question is I want a query through which i may know a particular user is accessing 1 session or already two session are active

Eg

user name :: session activated

abc ::1

manager ::1

xyz ::2

pqr :: 2

I know thru a license v can know activate but could find the sessional ....

Hope it tuff job bt nt like impossible in today world....