PHP数据库查询类-完整版

<?php
//$sql="select * from `table` where 1";
//$sql="insert into `table` set `name`='asdfasdf',`passwd`='11111'";
//$sql="insert into `table` (`name`,`passwd`) values ('asdfasd','11111')";
//$sql="update `table` set `name`='112321',`passwd`='22222' where `id`='1'";
//$sql="delete from `table` where 1 and `id='1'`"
class mysql{
var $host="localhost";
var $port="3306";
var $user="root";
var $passwd="root";
var $db="";
var $charset="utf8";
var $conn;
function __construct($host,$port,$user,$passwd,$db,$charset="utf8"){
$this->host=$host;
$this->port=$port;
$this->user=$user;
$this->passwd=$passwd;
$this->db=$db;
$this->charset=$charset;
$this->connect();
}

function connect(){

$this->conn=@mysql_connect($this->host.":".$this->port,$this->user,$this->passwd) or die(mysql_error());
$this->select_db();
$this->charset();
}

function select_db(){
@mysql_select_db($this->db) or die(mysql_error());

}

function charset(){
@mysql_query("set names ".$this->charset) or die(mysql_error());
}

function query($sql){
$query=@mysql_query($sql);

return $query;

}
//以上数据库表链接成功；


function select($table,$where){

if(!empty($table)){
$sql="select * `".$table."`  where 1 ";
if(!empty($where)){
$sql=$sql." and ".$where;
}
$this->query($sql);
}else{
die("error");
}