I am trying to do this to calculate the LastDate is more then 15 mins in LINQ:
And DateTimeOffset.Now.Subtract(tbl.LastDate).Minutes >= 15
Method 'System.TimeSpan Subtract(System.DateTimeOffset)' has no supported translation to SQL.
You can use the EntityFunctions class to perform operations on dates, among other things.
And (tbl.LastDate >= EntityFunctions.AddMinutes(DateTime.Now, -15))
if you are not using entityfunction you can do that
DateTime oldestDate = DateTime.Now.AddMinutes(-15);
... then modified the where portion of the LINQ query
And (tbl.LastDate >= oldestDate )