Question

I got a table with some time data in the format of yyyymmddMilliseconds. For example, 20100218000051234. How to convert this into DateTime type? In SQL Server 2008.

Answer 1

Interestingly, if you are using SQL Server 2005 and prior, you won’t get the exact precision you want because DateTime values are rounded to increments of .000, .003 or .007. Thus, 51.234 becomes 51.233. However, if you use DateTime2, you can get the precision you want:

declare @x varchar(50)
set @x='20100218000051234'
Select DateAdd(ms, Cast(Substring(@x, 9, 9) As int), Cast(Substring(@x, 1, 8) As datetime))
Select DateAdd(ms, Cast(Substring(@x, 9, 9) As int), Cast(Substring(@x, 1, 8) As datetime2))

Results:
2010-02-18 00:00:51.233 
2010-02-18 00:00:51.2340000