SQL Keys and Normalization | Dataford Interview Questions

What are the common keys in SQL, and how do you approach normalization techniques?

Using the provided normalized tables, write a query that demonstrates how related records are connected through their keys and summarizes order activity for every customer.

Output

One row per customer with customer_name, order_count, and total_quantity.
Include customers without orders, treating their counts and quantity as zero.
Sort by customer_id ascending.

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_date	DATE	Date the order was placed

order_items

Column	Type	Description
order_item_idPK	INT	Unique order item identifier
order_id	INT	Order containing the item
product_code	VARCHAR(30)	Product code
quantity	INT	Quantity recorded for the item

Whenever you're ready, walk me through your approach or go straight to the code. The requirements and the three tables are in the Question tab.

Problem