← SQL Analyst Starter
Lesson 3 of 4
Join and keep unmatched orders
Use a left join for a complete order list.
Do the work
- Join orders.customer_id to customers.customer_id.
- LEFT JOIN keeps unmatched and NULL-key orders.
- A missing name remains SQL NULL, not an empty string.
See the method
Orders are the left table.
Read every demonstration step
- Orders are the left table.
- Join customers by their ID.
- Order 5 has no matching customer and remains in the output.
Practice independently
Exercise 1
Attach names to every order
Open practice →Exercise 2Find customers without orders
Open practice →Take it further
Joining by email would duplicate customers sharing an email.