Try this...
Select * From TableName t
where not exists (Select t2.EmpId From TableName t2 where t2.SensorId =3 and t2.EmpId=t.EmpId)
If you want the Records who has not log out on that particular day...
Select * From #Temp t
where not exists (Select t2.EmpId From #Temp t2 where t2.SensorId =3 and t2.EmpId=t.EmpId and DATEDIFF(D,t.CheckTime,t2.CheckTime)=0) and t.SensorId <>3
Tested...
Create table #Temp(EmpId Int, CheckTime DateTime, SensorId Int)
Insert into #Temp
Select '1234','2010-06-30 07:31',1 Union all
Select '253','2010-06-30 08:31',2 Union all
Select '1234','2010-06-30 18:31',3
Select * From #Temp t
where not exists (Select t2.EmpId From #Temp t2 where t2.SensorId =3 and t2.EmpId=t.EmpId)
Drop Table #Temp
Output:
EmpId CheckTime SensorId
----- ----------- ---------
253 2010-06-30 08:31:00.000 2