仅更新SQL Server 2008中的datetime列的时间部分

UPDATE tblAttendance2 
SET 
    DateTimeIn = CONVERT(varchar(10), DateTimeIn, 120) + @TimeInChange,
    DateTimeOut = CONVERT(varchar(10), DateTimeIn, 120) + @TimeOutChange
WHERE 
    AttendanceDeductionsID = @AttendanceDeductionsID
UPDATE tblAttendance2 
SET 
    DateTimeIn = CO