T-SQL实现IP排序

今天群里有人在问如何用sql对IP地址进行排序，首先想到的是把IP切割，但是用substring太麻烦了，于是就百度到了T-SQL拆分IP地址 这边文章，PARSENAME真是个好东西，

用起来真是太丝滑了，然后就结束了

与此同时，还用C#代码写了个扩展方法也实现了对IP字段的排序：

public static ICollection<string> Order(this ICollection<string> ips, bool asc = true)
{
    if(ips==null)
        throw new ArgumentNullException(nameof(ips));
    foreach (var ip in ips)
    {
        IPAddress tmp;
        if (!IPAddress.TryParse(ip, out tmp))
        {
            throw new Exception("Illegal IPAdress data.");
        }
    }
    Func<string, int, int> func = (s, i) =>
    {
        var tmp = s.Split('.');
        return int.Parse(tmp[i]);
    };
    if (asc)
    {
        return ips.OrderBy(m => func(m, 0))
            .OrderBy(m => func(m, 1))
            .OrderBy(m => func(m, 2))
            .OrderBy(m => func(m, 3))
            .ToList();
    }
    return ips.OrderByDescending(m => func(m, 3))
        .OrderByDescending(m => func(m, 2))
        .OrderByDescending(m => func(m, 1))
        .OrderByDescending(m => func(m, 0))
        .ToList();
}