sql 随机抽取数据
查了好多资料，都是newid()。可是newid()太慢了，需要等好几分钟

[解决办法]

C# code

  private static int GetNewSeed()        {            byte[] rndBytes = new byte[4];            RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();            rng.GetBytes(rndBytes);            return BitConverter.ToInt32(rndBytes, 0);        }