MYSQLi PHP function fetch array - php

Question

I am trying to retrieve a zone by running a PHP function based off of a place that has already been submitted.
Using FORM method GET, after submission, the variable that I am retrieving is:
$place = mysqli_real_escape_string($_GET['place]);
The variable immediately after is zone:
$zone = getZone($pol); // here is the PHP function call
Above both of these variables is the function getZone, which looks like this:
function getZone($place)
{
$searchZone = "SELECT ZONE FROM zones WHERE PLACE = '".$place."'";
$result = mysqli_query($dbc, $searchZone);
$row = mysqli_fetch_array($result);
return $row['ZONE'];
}
I can run the query in the database, and it returns the ZONE.
Now, the mysqli_fetch_array, which normally works for me, is failing to produce the result from the query.
Does anyone see what is wrong?

Answer 1

You've forgotten about PHP's variable scope rules:
$result = mysqli_query($dbc, $searchZone);
^^^^---- undefined
Since $dbc is undefined in the function, you're using a local null handle, which is invalid. If you'd had ANY kind of error handling in your code, you'd have been told about the problem.
Try
global $dbc;
$result = mysqli_query(...) or die(mysqli_error($dbc));
instead. Never assume success. Always assume failure, check for that failure, and treat success as a pleasant surprise.

Answer 2

This might help
//Assuming $dbc as connection variable
function getZone($dbc,$place)
{
$searchZone = "SELECT ZONE FROM zones WHERE PLACE = '".$place."'";
$result = mysqli_query($dbc, $searchZone);
$row = mysqli_fetch_array($result);
return $row['ZONE'];
}
include 'path/to/connectionfile';//Only if you haven't already done that
$zone = getZone($dbc,$pol);

Answer 3

Ok... I figured it out, thanks to the assistance of Marc B. I took into account that I was not providing my connection string, so I added it to the file. Problem is, I needed to add it to the actual function, like so:
function getZone($place)
{
include ("../include/database.php");
// then the rest of the code
After I included the database connection, I am now able to retrieve the zone.
Thank you.