DATE AND TIME please note the following points syntax datetime2[(fractional seconds precision)] Precision, scale 0 to 7 digits, with an accuracy of 100ns. The default precision is 7 digits. Storage Size 6 bytes for precision less than 3; 7 bytes for precision 3 and 4. All other precision require 8 bytes. DateTime2 with fractional seconds precision of 3 is same as DateTime data type. And DateTime2(3) uses 7 bytes of storage instead of 8 byte () Find more on datetime2(Transact-SQL MSDN article) image source : MCTS Self-Paced Training Kit (Exam 70-432): Microsoft® SQL Server® 2008 - Implementation and Maintenance Chapter 3:Tables -> Lesson 1: Creating Tables -> page 66