mysqli_query not working when called from inside a function [duplicate] - php

Question

This question already has answers here:
Reference: What is variable scope, which variables are accessible from where and what are "undefined variable" errors?
(3 answers)
Closed 7 years ago.
Here is my code:
<?php
$db_host = 'localhost';
$db_user = 'root';
$db_pass = 'root';
$db_database = 'drmahima_com';
$link = mysqli_connect($db_host,$db_user,$db_pass,$db_database) or die('Unable to establish a DB connection');
mysqli_query($link, "SET names UTF8");
function temp() {
$patient = mysqli_fetch_assoc(mysqli_query($link, "SELECT name,dob FROM patients WHERE id='69'"));
echo $patient['name'];
}
temp();
?>
When I run this, the query doesn't seem to execute and nothing shows up on the page. However, if I remove the function and just change the code to this:
<?php
$db_host = 'localhost';
$db_user = 'root';
$db_pass = 'root';
$db_database = 'drmahima_com';
$link = mysqli_connect($db_host,$db_user,$db_pass,$db_database) or die('Unable to establish a DB connection');
mysqli_query($link, "SET names UTF8");
// function temp() {
$patient = mysqli_fetch_assoc(mysqli_query($link, "SELECT name,dob FROM patients WHERE id='69'"));
echo $patient['name'];
// }
// temp();
?>
It works, and the patient's name is displayed.
What is going on here?

Answer 1

Pass the $link to function as a parameter. Try this:
<?php
$db_host = 'localhost';
$db_user = 'root';
$db_pass = 'root';
$db_database = 'drmahima_com';
$link = mysqli_connect($db_host,$db_user,$db_pass,$db_database) or die('Unable to establish a DB connection');
mysqli_query($link, "SET names UTF8");
function temp($link) {
$patient = mysqli_fetch_assoc(mysqli_query($link, "SELECT name,dob FROM patients WHERE id='69'"));
echo $patient['name'];
}
temp($link);
?>

Answer 2

Pass $link to the function. It is not working because of the scope of that variable. Try with -
function temp($link) {
$patient = mysqli_fetch_assoc(mysqli_query($link, "SELECT name,dob FROM patients WHERE id='69'"));
echo $patient['name'];
}
temp($link);