Why is My PHP Code Throwing a 'Call to Undefined Function mysqli_connect()' Error on the New Server?

Fatal Error: Resolving "Call to Undefined Function mysqli_connect() at New Hosting Destination

Problem Statement:

While migrating an application dealing with reviews to a new hosting site, the developer encountered the error "Fatal error: Call to undefined function mysqli_connect()." This issue did not occur on the original hosting server, despite using identical code that also functioned on a local host.

Code Snippet:

$con = mysqli_connect("","*the_name*","*the_pass*","*the_database*");
if (mysqli_connect_errno()) {
    echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

Cause of the Error:

The error typically indicates that the MySQL extension for PHP is not available on the new hosting site. Without this extension, the mysqli_connect() function cannot be executed.

Solution:

To resolve the error, the PHP-MySQL extension needs to be installed on the new hosting server. Execute the following command in the terminal:

sudo apt install php-mysqli

Rationale:

sudo apt install php-mysqli updates the system database to include the necessary dependencies for running MySQL extension. It retrieves and compiles the extension, making mysqli_connect() and other MySQL functions available for use.

Additional Note:

The solution provided in the question using sudo apt install php7.2-mysqli may not be applicable in all cases, as it specifies a specific PHP version. Using php-mysqli ensures compatibility across different versions of PHP.

The above is the detailed content of Why is My PHP Code Throwing a 'Call to Undefined Function mysqli_connect()' Error on the New Server?. For more information, please follow other related articles on the PHP Chinese website!