create index [OrderDate_IX] on Purchasing.PurchaseOrderHeader (OrderDate) set statistics io on set statistics time on select PurchaseOrderID,OrderDate from Purchasing.PurchaseOrderHeader where OrderDate >= '20050517' and OrderDate < '20050518' select PurchaseOrderID,OrderDate from Purchasing.PurchaseOrderHeader where cast(OrderDate as Date) = '20050517'They both will use an Index Seek, but there is a slight bit of additional overhead using the CAST that results in an increased execution time of anywhere from 20-80 milliseconds. I generally avoid expressions in a WHERE clause where I can - so I would say the first approach is technically better. It's an old trick developers (especially those writing reports) have used for years....to retrieve all the rows that are greater than or equal to midnight of a start date, and less than midnight of (final date that you want, plus one day)