Linq无聊练习系列2--select/distinct练习

void dataBindByWhere()
        {

/**************select/distinct 练习*******************/
            //获取数据库中的T_Student表数据
            var list = from s in ctx.T_Student
                       select s;
            //采用匿名类型
            var list1 = from s in ctx.T_Student
                        select new
                        {
                            stuNumber = s.stuNumber,
                            stuSex = s.stuSex,
                            //这里边是可以计算的
                            stuAge = s.stuAge / 2 + s.stuAge / 2,
                            //也可以进行条件判断
                            stuAgeTime = s.stuAge>20?"成年":"年轻",
                            stuName = s.stuName
                        };
            //也可以不用匿名类型获取个别字段值
            var list2 = from s in ctx.T_Student
                        select s.stuName;
            //也可以转化为自定义的类型,比如这里的peple为自定义的类型
            var list3 = from s in ctx.T_Student
                        select new People
                            {
                                stuNumber = s.stuNumber,
                                stuName = s.stuName
                            };
            //可以在select 匿名类型里边继续包括匿名类型
            var list4 = from s in ctx.T_Student
                        select new
                        {

stuNumber = s.stuNumber,
                            stuName = s.stuName,
                            stuInfo = new T_Student { stuAge = s.stuAge, stuSex = s.stuSex }
                        };
            //也可以继续在select 里边包括select
            var list5 = from s in ctx.T_Student
                        select new {
                            stuNumber = s.stuNumber,
                            stuSCore = from c in s.T_Score
                                       where s.stuNumber==c.stuNumber
                                       select c.score
                        };
            //也可以在select 里边调用方法
            var list6 = from s in ctx.T_Student
                        select new {
                            stuNumber = s.stuNumber,
                            stuName = s.stuName,
                            stuAge = AgeInfo(s.stuAge)
                        };
            //也可以对查询结果去除重复
            var list7 = (from s in ctx.T_Student
                         select s.stuName).Distinct();
            GridView1.DataSource = list;
            GridView1.DataBind();
        }
        string AgeInfo(int age)
        {
            return age > 20 ? "成年" : "年轻";
        }