SQL Server 2008: Ordering by datetime is too slow

Question

My table (SQL Server 2008) has 1 million+ records, when I try to order records by datetime, it takes 1 second, but when I order by ID (int), it only takes about 0.1 second.<

Answer 1

Could it be that there is an index for your int column but not for your datetime column? Look at the execution plan.