remove duplicate output from custom sql query, how?

Hello, I am trying to find out how to remove duplicate results (users in this case) from the output.

I have a customer who has an RDS portal with a Fortigate captive portal where users have to enter their credentials and fortitoken code. The customer wants to know whether a user has logged in via the rds portal in the last month.  I found the log that shows when a user succesfully logs in and then created a dataset that will show date, user and client source ip.

I created the chart with the dataset and a report template that will create a report with last months logins.

However if a user had logged in several times (what happens of course) I only want to have 1 result.

What needs to be added in the query? Second, is there a way to remove the default 'succeeded in authentication' text from the 2nd column?

Thanks for any help,

Ralph Willemsen

Arnhem, Netherlands