Focus on the query, not the PHP. There's even a Tek-Tips forum to focus on MySQL. [bigsmile]
https://www.mysqltutorial.org/mysql-left-join.aspx
SELECT
`order_id`, `customer_id`, `order_item`, `order_date`, `order_value`, `customer_name`
FROM
`tbl_order_id`
LEFT JOIN `customers` ON...