How to solve php mysql_query error problem

php mysql_query error solution: 1. Use the code "$db=$db?$db:new mysqlClass();"; 2. Use the code "$this->link=mysql_connect($host ,$user,$pw,true);”.

The operating environment of this article: windows7 system, PHP7.1 version, DELL G3 computer

PHP error Warning: mysql_query() solution Method

php prompt error: Warning: mysql_query() [function.mysql-query]: Access denied for user 'ODBC'@'localhost' (using password: NO)

Code:

<?php 
class mysqlClass 
{ 
function mysqlClass($host=&#39;localhost&#39;,$user=&#39;root&#39;,$pw=&#39;&#39;,$db=&#39;mysql&#39;) 
{ 
$this->link=mysql_connect($host,$user,$pw); 
mysql_select_db($db); 
} 
function query($sql){ 
mysql_query($sql); 
} 
function __destruct(){ 
mysql_close($this->link); //multi construct will cause error 
} 
// liehuo,net 
} 
$db=new mysqlClass(); 
$db=new mysqlClass(); 
$db->query("select * from user");

Reason:

When mysqlClass is initialized for the second time, mysqlClass is initialized first and the same $this- is obtained as the first $db. >link, and then calling the __construct function will close this->link.

Finally, the mysql resource in $db is empty and an error pops up.

Solution:

$db=$db?$db:new mysqlClass();　

or

$this->link=mysql_connect($host,$user,$pw,true);

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