explode results then implode php - php

Question

I'm getting the contents of a column which has contents stored as 3,2 then I'm using the explode function to separate them. The values separated are then used to query another table to bring names. Next I want to implode the results like burger, fries. But the results are not separated by the comma but are like burgerfries... This is what I have done:
$sql = "SELECT items FROM orders";
$result = mysqli_query($connection, $sql);
$array = mysqli_fetch_assoc($result);
$exploded = explode(",", $array['items']);
foreach ($exploded as $row){
$query = "SELECT food_name FROM foodlist WHERE food_id = $row";
$res = mysqli_query($connection, $query);
$arr = mysqli_fetch_assoc($res);
$imploded = implode(", ", $arr);
echo $imploded;
}

Answer 1

Because every $arr only contains one ingredient, so you're actually implode()ing just one element, echoing it, and then echoing other ingredients not separated by anything, so they show together.
You can add them to an array and then implode them:
$sql = "SELECT items FROM orders";
$result = mysqli_query($connection, $sql);
$array = mysqli_fetch_assoc($result);
$exploded = explode(",", $array['items']);
$ingredients = [];
foreach ($exploded as $row){
$query = "SELECT food_name FROM foodlist WHERE food_id = $row";
$res = mysqli_query($connection, $query);
$arr = mysqli_fetch_assoc($res);
$ingredients[] = $arr["food_name"];
}
echo implode(", ", $ingredients);
PRO TIP, it's a bad idea to have your fields separated by a comma like that in the database. You should normalize that field, have another table called ingredients and a pivot table called order_ingredient containing every ingredient a specific order has, then you can simply JOIN the ingredients by ID and get them all at once, instead of doing N+1 queries which will kill your performance fast.
The structure would look like this:
And the query something like
SELECT ingredient FROM orders o JOIN order_ingredient oi ON oi.order_id = o.id JOIN ingredients i ON oi.ingredient_id = i.id
which will return all your ingredients with just one query.

Answer 2

I see that you have already accepted an answer.
If you want to substantially reduce the number of queries you're executing, you could use the following single query to get a comma separated list of food items for all orders.
SELECT o.id, GROUP_CONCAT(f.name SEPARATOR ', ') AS food
FROM orders o
INNER JOIN food f ON FIND_IN_SET(f.id, o.items) > 0
GROUP BY o.id
Here's an SQL fiddle to demonstrate: http://sqlfiddle.com/#!9/b0004c/2
But the correct solution would be to normalize your database structure.