一次偶然的机会，一客户代码基于PHP5开发，发给我处理代码问题，无耐本地测试环境早已升级成了PHP7，打开页面就报如下错误：
Fatal error: Uncaught Error: Call to undefined function mysql_connect() in dir/index.php:8 Stack trace: #0 {main} thrown in dir/index.php on line 8
很明显，PHP7已经抛弃了mysql_connect，如何兼容呢？下面贴出兼容代码：
<?php
if(!function_exists('mysql_connect')){
function mysql_connect($dbhost, $dbuser, $dbpass){
global $dbport;
global $dbname;
global $mysqli;
$mysqli = mysqli_connect($dbhost, $dbuser, $dbpass, $dbname);
return $mysqli;
}
function mysql_select_db($dbname){
global $mysqli;
return mysqli_select_db($mysqli,$dbname);
}
function mysql_fetch_array($result){
return mysqli_fetch_array($result);
}
function mysql_fetch_assoc($result){
return mysqli_fetch_assoc($result);
}
function mysql_fetch_row($result){
return mysqli_fetch_row($result);
}
function mysql_query($query){
global $mysqli;
return mysqli_query($mysqli,$query);
}
function mysql_escape_string($data){
global $mysqli;
return mysqli_real_escape_string($mysqli, $data);
}
function mysql_real_escape_string($data){
return mysql_real_escape_string($data);
}
function mysql_close(){
global $mysqli;
return mysqli_close($mysqli);
}
}注意，上面$dbhost可能需要带正确的端口。
