Fatal error: Uncaught Error: Call to undefined function mysql_error

I have same issue after creating a backup using duplicator and restoring it on my local machine

Hi! untill now I could not fix it. Some guy gave me this link with a possible solution, but do not worked for me.

Look: https://stackoverflow.com/questions/8225198/phpmyadmin-the-mysql-extension-is-missing/8225474#8225474

I hope it works for you!

Hi Guys!

I had the same problem. According to the mysql specs the function mysql_error was deprecated in PHP 5.5 and removed in PHP 7.0.

See: mysql_error

It’s the revslider plugin that doesn’t conform to the latest API.

I am using one.com and was able to downgrade PHP to version 5.6 in the control panel.

Problem solved!

Hi! thanks for the answer.
So, if I use the version 5.6 of PHP, this should work.

I will try and I will tell you what happened.

Thanks you!

Downgrading from php 7 to a 5.x version as a fix? Hmmm…there must be a better way.

My understanding is that updating to the latest version of the Slider Revolution plugin corrects the incompatibility with PHP 7. I haven’t tried it yet, but will let report back on what I find out after testing it. Another possible solution is to alter the plugin code so that it checks whether the function exists before calling it, as described here: https://premium.wpmudev.org/forums/topic/revolution-slider-network-activate-failed

mysql_error was removed from PHP7.0.0 so best way is change to mysqli_error

Here’s a quick fix that worked for me…

Change line 29 of db.class.php from:
if(mysql_error()){

to:

if(mysqli_error()){

• This reply was modified 7 years, 11 months ago by iannerney.

please where is db.class.php?

If you’re still looking, it’s in /wp-content/plugins/revslider/inc_php/framework/

To solve above error, please open file revslider/inc_php/framework/db.class.php and go to line no 29.

You need to replace this code

if(mysql_error()){
	$query = $this->wpdb->last_query;
	$message = $this->wpdb->last_error;

	if($prefix) $message = $prefix.' - <b>'.$message.'</b>';
	if($query) $message .=  '<br>---<br> Query: ' . $query;

	$this->throwError($message);
}

with this one

private function checkForErrors($prefix = ""){
	global $wpdb;
	
	if($wpdb->last_error !== ''){
		$query = $wpdb->last_query;
		$message = $wpdb->last_error;
		
		if($prefix) $message = $prefix.' - <b>'.$message.'</b>';
		if($query) $message .=  '<br>---<br> Query: ' . esc_attr($query);
		
		$this->throwError($message);
	}
}