SQL Joins and Left Join | Dataford Interview Questions

Explain joins in SQL and how LEFT JOIN differs from INNER JOIN.

Use the provided customers and orders tables to demonstrate the difference with a query. The result should make unmatched customers visible and allow comparison with the matching-only behavior.

Output

One row per customer and matching order, including customers without orders
Columns: customer_id, customer_name, order_id, and order_status
Sort by customer_id ascending, then order_id ascending, with missing order IDs last

Schema

customers

Column	Type	Description
customer_idPK	INT	Unique customer identifier
customer_name	VARCHAR(100)	Customer display name

orders

Column	Type	Description
order_idPK	INT	Unique order identifier
customer_id	INT	Customer associated with the order
order_status	VARCHAR(30)	Current order status

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Problem