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 原文：http://www.cnblogs.com/wucg/archive/2010/10/13/1850053.html

static void Main() 
        { 
            string strcon = global::TestLinqToSQL.Properties.Settings.Default.testConnectionString; 
            SqlConnection conn = new SqlConnection(strcon); 
            SqlDataAdapter da = new SqlDataAdapter("select * from T_Teacher", strcon); 
            DataTable dt = new DataTable(); 
            da.Fill(dt); 
            conn.Close(); 
            IEnumerable<DataRow> q1 = from r in dt.AsEnumerable() 
                                      where r.Field<int>("ID") % 2 == 0 
                                      select r; 
            foreach (var item in q1) 
            { 
                Console.WriteLine("ID={0},Name={1},Birthday={2}", item["ID"].ToString(), item["Name"].ToString(), item["Birthday"].ToString()); 
            } 
            Console.WriteLine("-----------------------------------"); 
            IEnumerable<DataRow> q2 = from r in dt.AsEnumerable() 
                                      where r.Field<int>("ID")>10 
                                      select r; 
            foreach (var item in q2) 
            { 
                Console.WriteLine("ID={0},Name={1},Birthday={2}", item["ID"].ToString(), item["Name"].ToString(), item["Birthday"].ToString()); 
            } 
            Console.WriteLine("-----------------------------------"); 
            DataTable dt1 = q1.CopyToDataTable(); 
            DataTable dt2 = q2.CopyToDataTable(); 
     //集合排除
            //var except = dt2.AsEnumerable().Except(dt1.AsEnumerable() , DataRowComparer.Default); 
            //集合并 
            //var except = dt2.AsEnumerable().Union(dt1.AsEnumerable(), DataRowComparer.Default); 
     //集合交 
            var except = dt2.AsEnumerable().Intersect(dt1.AsEnumerable(), DataRowComparer.Default); 
            foreach (var item in except) 
            { 
                Console.WriteLine("ID={0},Name={1},Birthday={2}", item["ID"].ToString(), item["Name"].ToString(), item["Birthday"].ToString()); 
            } 
            Console.WriteLine("done"); 
            Console.ReadLine(); 
        }