I am struggling to find an answer to this issue.

I have a table where I can have multiple order ids for one customer (email)

```
email (unique), order_id

```

I need to make a query where I pass in any order\_id for a customer, and it returns ALL their orders. 

I have two select queries I need to combine into one query to save on load time.

```
SELECT email FROM orders WHERE order_id = '1234567890'

SELECT order_id FROM orders WHERE email = 'email_found_from_first_query'

```