当php函数从mysql数据值中选择时，“未定义的变量”

Question

A newbie question. There must be an easy answer to this but I have spent hours searching, including here in StackOverflow (also in Duplicate Questions), to no avail. Please help.

I have a Table inside a Database which I am trying to iterate.

Simplified Table is as follows:
id(int,auto-increment), product_name(varchar), price1(int)

1, widget1, 1000
2, widget2, 900
etc.

when I use this code, it works

    <?php
    $connection = mysqli_connect("localhost", "root", "", "test");

    $item = 'widget1';
    $sql = "SELECT * FROM gym_eqpt WHERE product_name = '$item' ";
    $results = mysqli_query($connection, $sql);
    while($result = mysqli_fetch_array($results)) {
    echo "<p>item name: " . ($result['product_name']) . "<br />" . "<p>item price: " . number_format($result['price1']) . " </p>";
}
?>

However, when I try to use the same code inside a function, there is an "Undefined variable" error.

<?php
function iteratePrice($item) {
    $sql = "SELECT * FROM gym_eqpt WHERE product_name = '$item' ";
    $results = mysqli_query($connection, $sql);
    while($result = mysqli_fetch_array($results)) {
    echo "<p>item name: " . ($result['product_name']) ."<p>item price: " . number_format($result['price1']) . " </p>";
    }   
}

iteratePrice('widget1');
?>

Eventually, I would like to use this function inside different html div's on the same page, calling each product name and price in each div.

Answer 1

All external variables are unknown inside a function so, it will be better if you pass external values as parameters:

function iteratePrice($connection, $item) {
    $sql = "SELECT * FROM gym_eqpt WHERE product_name = '$item' ";
    $results = mysqli_query($connection, $sql);
    while($result = mysqli_fetch_array($results)) {
    echo "<p>item name: " . ($result['product_name']) ."<p>item price: " . number_format($result['price1']) . " </p>";
    }   
}

And then call it as:

iteratePrice($connection, 'widget1');

This is the documentation about php functions and scope: http://php.net/manual/en/language.variables.scope.php