mysql php query steps

1.mysql connect 

   $db=new mysqli ('localhost','database','user','password');

2. query

    $query=select id from table_name where name='abc';

     $query=insert into table_name values("id","info");

3.value

   $results=$db->query($query);

   $num=$results->num_rows;

    for($i=0;$i<$num;$i++){

      $result_arr=$results->fetch_assoc();

      $value1=$result_arr['id];

}