in MySQL
select * from record where register_date like '2009-10-10%'
What is the syntax in SQL Server?
You could use the DATEPART() function
SELECT * FROM record
WHERE (DATEPART(yy, register_date) = 2009
AND DATEPART(mm, register_date) = 10
AND DATEPART(dd, register_date) = 10)
I find this way easy to read, as it ignores the time component, and you don't have to use the next day's date to restrict your selection. You can go to greater or lesser granularity by adding extra clauses, using the appropriate DatePart code, e.g.
AND DATEPART(hh, register_date) = 12)
to get records made between 12 and 1.
Consult the MSDN DATEPART docs for the full list of valid arguments.