in MySQL
select * from record where register_date like \'2009-10-10%\'
What is the syntax in SQL Server?
There's no direct support for LIKE operator against DATETIME variables, but you can always cast the DATETIME to a VARCHAR:
SELECT (list of fields) FROM YourTable
WHERE CONVERT(VARCHAR(25), register_date, 126) LIKE '2009-10-10%'
Check the MSDN docs for a complete list of available "styles" in the CONVERT function.
Marc