int[] arr = new int[100];
        for (int i = 0; i < 100; i++)
        {
            arr[i] = i;
        }

        var query = from i in arr where  i < 10  select i;
        int ii = query.Last<int>();
        Response.Write(ii.ToString() + "</br>");

        foreach (var item in query)
        {
            Response.Write(item.ToString());
            Response.Write("</br>");
        }

        DataTable dt = SqlDbHelp.Query("select distinct job_desc from jobs").Tables[0];

        var query2 = from dsLinq in dt.AsEnumerable()  where dsLinq.Field<string>("job_desc").Length > 5 select dsLinq;

// query = from dsLinq in dt.AsEnumerable()  where dsLinq.Field<string>("job_desc").Length > 5 select dsLinq;

 //这句话为什么会错

        foreach (var item in query2)
        {
            Response.Write(item.Field<string>("job_desc").ToString());
            Response.Write("</br>");
        }

问题1，SELECT写在后面有什么特殊含义没有，为什么这么写

问题2query = from dsLinq in dt.AsEnumerable()  where dsLinq.Field<string>("job_desc").Length > 5 select dsLinq;//这句话为什么会错