Rinat Abdullin

Microsoft SQL Server sorts uniqueidentifier columns in a way that is different from the Guid ordering in .NET (see this post by Alberto Ferrari).

Here's a small C# code snippet from Lokad.Shared that implements Sql Server sorting of Guids in .NET.

public sealed class SqlServerGuidComparer : IComparer<Guid>
{
  static readonly int[] _importance = new[] {3, 2, 1, 0, 5, 
    4, 7, 6, 9, 8, 15, 14, 13, 12, 11, 10};

  public int Compare(Guid x, Guid y)
  {
    var a = x.ToByteArray();
    var b = y.ToByteArray();

    for (int i = _importance.Length - 1; i >= 0; i--)
    {
      var compare = _importance[i];
      var c = a[compare].CompareTo(b[compare]);
      if (c != 0)
      {
        return c;
      }
    }
    return 0;
  }
}

BTW, you could use this comparer in the Linq method OrderBy, that takes a reference of IComparer{T}.