Call to undefined function mysqli_connect() code example
Example 1: Uncaught Error: Call to undefined function DatabaseOld\mysqli_connect()
sudo apt install php-mysqli
Example 2: call to undefined function mysql_connect()
Try checking to see if the PHP MySQL extension module is being loaded:
<?php
phpinfo();
?>
If it's not there, add the following to the php.ini file:
extension=php_mysql.dll
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