/*********************Any/All/Contains/Concat/Union/Intersect/Except/take/skip/SqlMethods操作练习**********************************/

            //判断没有成绩的学生

            var list = from s in ctx.T_Student

                       where !s.T_Score.Any()

                       select s;

            //判断有成绩大于80的学生

            var list1 = (from s in ctx.T_Student

                         where s.T_Score.Any(t => t.score > 80)

                         select s).Distinct();

            //所有科目成绩大于80的学生

            var list2 = from s in ctx.T_Student

                        where s.T_Score.All(t=>t.score>80)

                        select s;

            //查询黄阳是否参加过考试

            string[] names = { "黄阳"};

            var list4 = from s in ctx.T_Score

                        where names.Contains(s.T_Student.stuName)

                        select s;

            //查询黄阳是否参加过考试

            var list3 = from s in ctx.T_Score

                        where (new string[] { "黄阳" }).Contains(s.T_Student.stuName)

                        select s;

            //参加过考试但是不是黄阳的同学

            var list5 = from s in ctx.T_Score

                        where !(new string[] { "黄阳" }).Contains(s.T_Student.stuName)

                        select s;

            //contains也可以包含一个对象，如查询那些学生参加了课程编号为001的第一个同学，对于contains只能包含一个实体，不能保护实体集

            var temp1 = (from s in ctx.T_Score

                        where s.stuNumber == "001"

                        select s).First();

            var result = ctx.T_Student.Where(p=>p.T_Score.Contains(temp1));

            //查找黄阳和黄波的所有成绩

            string[] names1 = {"黄阳","黄波"};

            var result2 = ctx.T_Score.Where(f=>names1.Contains(f.T_Student.stuName));

            //或者也可以这样

            var result3 = from s in ctx.T_Score

                          where (new string[] { "黄阳", "黄波" }).Contains(s.T_Student.stuName)

                          select s;

            //对于concat，连接不同的集合，不会自动过滤相同项,而且它只能对于单列进行连接，对多列进行连接，会报语法错误，因为没有相应的扩展方法

            var result4 = (from s in ctx.T_Student

                           select s.stuName)

                          .Concat(from k in ctx.T_Score

                                  select k.T_Cource.courceName );

            //合并所有的学生

            var result5 = ((from s in ctx.T_Student

                            select s.stuNumber)

                        .Union

                        (from k in ctx.T_Score

                         select k.stuNumber)).Distinct();

            //交集

            var result6 = (from s in ctx.T_Student

                           select s.stuNumber).Intersect

                          (from k in ctx.T_Score

                               select k.stuNumber);

            //差集

            var result7 = (from s in ctx.T_Student

                           select s.stuNumber).Intersect

                               (from k in ctx.T_Score

                                select k.stuNumber);

            //查询前三个学生的信息

            var result8 = (from s in ctx.T_Student

                          select s).Take(3);

            //查询三个学生以外的所有学生信息

            var result9 = (from s in ctx.T_Student

                               select s).Skip(3);

            //当学号为2091723时候，就停止获取学生信息

            var result10 = (from s in ctx.T_Student

                            select s).TakeWhile(k => k.stuNumber == "2091723");

            //当学号为2091723时候，就停止跳过学生信息，并获取后边的所有学生信息

            var result11 = (from s in ctx.T_Student

                            select s).SkipWhile(k => k.stuNumber == "2091723");

            //可以用skip和take来对数据进行分页，这非常方便

            //查看姓名以黄开头的学生信息,这时候程序需要引入using System.Data.Linq.SqlClient;命名空间

            var result12 = from s in ctx.T_Student

                           where SqlMethods.Like(s.stuName,"黄%")

                           select s;

            //查询学号为2X917X2的学生

            var result13 = from s in ctx.T_Student

                           where SqlMethods.Like(s.stuNumber, "2_917_2")

                           select s;

            //比较时间的操作分别有：DateDiffDay、DateDiffHour、DateDiffMillisecond、DateDiffMinute、DateDiffMonth、DateDiffSecond、DateDiffYear ，也是sqlMethods方法，而数据库中的表并没有设计时间的字段，所以就不演示了

            //SQL语句进行编辑重新查询,需要引用命名空间using System.Data.Linq;

            var fn = CompiledQuery.Compile(

                (DB_StudentDataContext ctx1,string stuName)=>

                from s in ctx1.T_Student

                where s.stuName==stuName

                select s

                );

            var data1 = fn(ctx,"黄阳");

            var data2 = fn(ctx,"黄波");