Name of object in array causes a change in order - php

Question

With the following code:
//turn items into an array
$item_array = array('abc','xyz2','Good','nice-b');
//implode items, turn into string
$item_implode = join("','", $item_array);
//declare an overall array for result
$product_items = array();
$productList = array();
$result = $mysqli->query("SELECT Name, WebsitePrice as price, WebsiteStock as stock from table_products where Name IN ('$item_implode')");
if ($result->num_rows > 0) {
$x = 1;
// output data of each row
while($row = $result->fetch_assoc()) {
$product_items[$x]["Name"] = $row['Name'];
$product_items[$x]["price"] = $row['price'];
$product_items[$x]["stock"] = $row['stock'];
$x = $x + 1;
}
} else {
echo "0 results";
}
I'm getting this output:
abc- 99 - yes
xyz - 20 - yes
Good - 30 - yes
nice-b - 55 - yes
But when I use an item called Hello1 instead of Good, like this:
$item_array = array('abc','xyz2','Hello1','nice-b');
I'm getting this output:
abc- 99 - yes
Hello1 - 77 - yes
xyz - 20 - yes
nice-b - 55 - yes
Meaning that the name of the object is causing some change in the order of the array, and it becomes the second item, even though it should be the third one.
What's causing this?

Answer 1

Use ORDER BY FIELD(Name, 'abc','xyz2','Good','nice-b'); in your query. You could use $item_implode for reusability.
[Fetched from comments]

Answer 2

In the SQL world, order is not an inherent property of a set of data. Thus, you get no guarantees from your RDBMS that your data will come back in a certain order -- or even in a consistent order -- unless you query your data with an ORDER BY clause.
There is no guarantee that MySQL will return the results in the order you set the IDs in the IN clause.
Later edit: Based on your last comment you can do something like this:
if ($result->num_rows > 0) {
$product_items = array_flip($item_array);
// output data of each row
while($row = $result->fetch_assoc()) {
$product_items[$row['Name']] = array();
$product_items[$row['Name']]["Name"] = $row['Name'];
$product_items[$row['Name']]["price"] = $row['price'];
$product_items[$row['Name']]["stock"] = $row['stock'];
}
}