Linq 模糊查询。Countains StartsWith EndsWith Indexof截取字符串，都可以用在Linq查询语句里

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication2
{

    class Program
    {
        static void Main(string[] args)
        {
            List<student> list = new Program().Select("王");
            foreach (student data in list)
            {
                Console.WriteLine(data.sname);
            }
            Console.ReadLine();
        }
        
        private DataClasses1DataContext _Context = new DataClasses1DataContext();
        public List<student> Select(string name)
        {
            return _Context.student.Where(p => p.sname.StartsWith(name)
                || p.sname.EndsWith(name) || p.sname.IndexOf(name) != -1).ToList();
        }

        //public List<student> Select(string name)
        //{
        //    return _Context.student.Where(p => p.sname.StartsWith(name)).ToList();
        //}
        //public List<student> Select(string name)
        //{
        //    return _Context.student.Where(p => p.sname.IndexOf(name) != -1).ToList();
        //}
    }
    
}

SQl语句分组查询，倒序查询，表a表b查询，查询所有科目的成绩分数都在分数70分以上的名字

select name from score1 where chengji >70 group by name

select distinct name from score1 a where name in (select name from score1 b where chengji>70 and a.name=b.name)

查询最近一次登录时间的一条信息。倒序查询，查第一条

select top 1* from 表 order by 列名 asc                 desc

大家都知道Linq查询语句很像SQL的查询。

n.Name.StartsWith(Name)－－相当于A% n.Name.EndsWith(Name)  －－相当于%A n.Name.IndexOf(Name)!=-1 --相当于%A%

var listWhere = list.Where(n=>n.Name.StartsWith(Name)||n.Name.EndsWith(Name)||n.Name.IndexOf(Name)!=-1);

或

var listWhere = list.Where(n=>n.Name.Contains(Name));