Getting and Comparing Data in Foreach best pratice

Hi, sorry, when i mention table i wanted to say MySQL tables.

Here's an example:

PHP Code:

<?php
 foreach($things as $thing) {
    echo $thing['id'];
 }
?>

I want to use $thing['id'] to query another MySQL table to get child data from this ID. This will be showed in a Dashboard front page to calculate costs.