How to query latest dates for multiple records in table 1

[medici]

I have a table (UserLogons) containing logon records from five domain controllers. Each user (UserName) in the domin will have one record from each DC, including the last logon date (LastLogon) for that particular DC (which may be empty if a particular user was never authenticated by a particular DC). So each particular user will have a total of five rows in the table.

I need to produce a filtered list with ONE row per UserName, showing the most recent LastLogon date only, irregardless of which DC might have been used.

Any ideas on how to do this?

 

[PWise]

select UserName,max(LastLogon)
from UserLogons
group by UserName