public virtual void DateDiffSecond()
{
DateTime dt = new DateTime(1997, 8, 25, 0, 0, 0);
DateTime dt1 = new DateTime(1996, 1, 15, 10, 20, 30);
var expected = (dt - dt1).Seconds;
var actual = db.Orders.Select(o => o.OrderDate == dt && SqlMethods.DateDiffSecond(o.OrderDate, dt1) == expected).FirstOrDefault();
Assert.IsNotNull(actual);
var expected1 = (dt - dt1).TotalSeconds;
#if Oracle
var item = db.Orders.Where(o => o.OrderDate == dt && SqlMethods.DateDiffSecond(dt1, o.OrderDate)+1 == (int)expected1).FirstOrDefault();
Assert.IsNotNull(item);
#else
var item = db.Orders.Where(o => o.OrderDate == dt && SqlMethods.DateDiffSecond(dt1, o.OrderDate) == (int)expected1).FirstOrDefault();
Assert.IsNotNull(item);
#endif
}