Regarding the problem of custom methods in mysqli, please solve it?

Question

When using $mysqli in a custom function, an error is reported. The red line at the bottom of $mysqli indicates

Although $mysqli reports a syntax error, it is marked with a red line. , but the data is still queried, but the loading is super slow, taking dozens of seconds, which is obviously abnormal

This is the database configuration

Answer 1

It is recommended to place require 'mysqli_connect.php'; outside the custom function, at the top of the program. Using the $mysqli variable in a function requires a global declaration. Write global $mysqli;

at the top of the function body.