面试题目总结

1.产生1000个不重复的随机数

/// <summary>
    /// 产生不重复随机数的方法
    /// </summary>
    /// <param name="minValue">最小值</param>
    /// <param name="maxValue">最大值</param>
    /// <param name="count">共产生多少随机数</param>
    /// <returns>int[]数组</returns>
    public int[] GetRandomUnrepeatArray(int minValue, int maxValue, int count)
    {
            Random rnd = new Random();
            int length = maxValue - minValue + 1;
            byte[] keys = new byte[length];
            rnd.NextBytes(keys);
            int[] items = new int[length];
            for (int i = 0; i < length; i++)
            {
                items[i] = i + minValue;
            }
            Array.Sort(keys, items);
            int[] result = new int[count];
            Array.Copy(items, result, count);
            return result;
     }
    public void Set_Random()
    {
        //调用产生随机数的方法产生的数据数是1111111到9999999之间的随机数输出10个
        int[] items = this.GetRandomUnrepeatArray(1111111, 9999999, 10);
        for (int i = 0; i < items.Length; i++)
        {
            Response.Write("产生的随机数是:" + items[i] + "<br/>");
        }
    }

2 SQL去除不要的字符

replace()

3. 复制表数据和结构

create b select * from a

4.sql A(a,b,c,d) b(c,e,d,f) 显示 a b c d e f

select * from a union select * from b