Employee timecard implementation: Need help for db select query

Project Description:
Hello,
I am implementing basic employee time management functionality where I need your help in creating a data base query to
look up last action performed by the user. I have never done any SQL programming so your help would be appreciated.

My Table is: TimeCards

Id int primarykey,notnull
TimeStamp datetime notnull
Action tinyint not null,
User_Id int FK (User.Id, not null)


I have a class TimeCardEntry as below

class TimeCardEntry : IEntity
{
enum TimeCardAction
{
None = 0,
ClockIn = 1,
ClockOut = 2;
}
public TimeCardEntry(User user, TimeCardAction action)
{
_user = user;
Action = (int)action;
TimeStamp = DateTime.Now;
}
public int Id { get; set; }
public int Action { get; set;}
public DateTime TimeStamp { get; set;}
public User User { get { return _user; } set { _user = value; }

private User _user;
}



I need to retrieve a last entry from TimeCards table where

1. TimeCardEntry.User.Id
2. TimeCardEntry.TimeStamp > DateTime.Today (Basically last entry today 12:00 AM)

I tried following function but getting exception.

TimeCardEntry GetLastTimeCardEntry(User user)
{

var entry = Dbo.Select(x=> x, (x=> x.User.Id == user.Id && (DateTime.Compare(x.TimeStamp, DateTime.Today) > 0)).Last()

return entry;
}