在LINQ查询中将时间戳比较为byte []

Question

I've got a byte array that I need to compare to a SQL column, timestamp, which is also a byte array. It's a timestamp that I need to get all records before or after from.

I'm using EF, and trying to get it to work in a LINQ query.

byte[] myArray = repo.GetTimeStampByDate(DateTime.Now);
rec.sometable.Where(o => o.timestamp <= myArray).ToList();

Answer 1

The easiest way is to convert both byte arrays to UInt64 values and then compare them.

Alternatively, you can create a custom method to compare timestamp arrays:

 // assuming both arrays are of equal lengths
 public static int Compare(byte[] ts1, byte[] ts2)
    {
        int i = 0;
        while (i < ts1.Length)
        {
            if (ts1[i] > ts2[i])
                return 1;
            else if (ts1[i] < ts2[i])
                return -1;
            ++i;
        }
        return 0;
    }

and then

byte[] myArray = repo.GetTimeStampByDate(DateTime.Now);
rec.sometable.Where(o => Compare(o.timestamp, myArray) <= 0).ToList();