MySQL INNER JOIN not returning expected rows when using LEFT JOIN on derived table
This might be a silly question, but I'm working with an scenario where my INNER JOIN is not returning the expected rows when I use a LEFT JOIN on a derived table. I'm using MySQL version 8.0.25. The goal is to retrieve all records from `orders` and their corresponding `customers`, but only if the customers have completed at least one order. Here's the query I'm currently using: ```sql SELECT o.order_id, c.customer_name FROM orders o INNER JOIN ( SELECT customer_id FROM orders WHERE status = 'completed' ) AS completed_orders ON o.customer_id = completed_orders.customer_id LEFT JOIN customers c ON o.customer_id = c.customer_id; ``` I expect to see all orders along with their customer names, but it seems that the LEFT JOIN on the `customers` table is not working as intended. Instead, I'm only getting orders from customers who have completed orders, and those without any completed orders are missing from the result set entirely. I've tried changing the order of the joins and rewriting the derived table to include a COUNT aggregation, but those approaches led me to syntax errors or even less expected results. When I execute the query, I only get 50 rows back, while I know there are over 100 orders in total. I would appreciate any insights or best practices on how to structure this query correctly to achieve the desired output. Is there a common pitfall in using INNER and LEFT JOINs together that I might be missing? Has anyone else encountered this?