Finding a user that has multiple log-ins at the same time

I have a table that contains the following

UserName - Which is unique to each user

TimeStart - Which is the time and date that the user logs in

TimeEnd - Which is the time and date that the user logs out

Using SQL, how do you find who has logged in using the same account within the same time period. In other words, Two people are using the same username and are logged in at the same time.

Try this query....

Select
MainQ.*
From
UserLog MainQ
Join
(
Select

Main.UserName,
Main.TimeStart,
Main.TimeEnd
From
UserLog Main
Join UserLog Started On Main.UserName = Started.UserName
And Main.TimeStart <= Started.TimeStart
And Main.TimeEnd >= Started.TimeStart

Group BY
Main.UserName,
Main.TimeStart,
Main.TimeEnd
Having Count(*) <> 1
) as Data
On MainQ.UserName = Data.UserName
And MainQ.TimeStart >= Data.TimeStart
And MainQ.TimeStart <= Data.TimeEnd