PHP and MYSQLI Error, Call to a member function query() on a non-object [duplicate]

Answer 1

 $link = mysqli_connect($hostname, $dbusername, $dbpassword, $dbname); 
 /////

 $result = $mysqli->query($sql);
           ///////

Answer 2

In your code you're mixing both procedural and object-oriented code. Choose either one or the other. Here's how you would solve the problem the procedural way.

$result = mysqli_query($link, $sql, MYSQLI_USE_RESULT)

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I'm getting the Call to a member function query() on a non-object when I try to call my function.

That's because the $mysqli object is not declared anywhere (or is it)? Before you can use $mysqli you should first create an instance of mysqli and assign it to your object.

$mysqli = new mysqli("localhost", "my_user", "my_password", "database");

Only then you may call the methods of the mysqli class like $mysqli->query();

The error you made depends probably on two misconceptions:

1) you pasted half of your code from the procedural-style part of the mysqli manual and half from the oop part

2) you assume $mysqli is a global object instantiated with $mysqli_connect();. It is not. You should invoke the constructor with the new keyword if you'd like to use it as an object.