[Solved] Given tables orders and customers, what will the following query return?SELECT customers.name, orders.id FROM customers LEFT JOIN orders ON customers.id = orders.customer_id WHERE orders.id IS NULL; | SQL

SQL - Advanced Joins

Given tables orders and customers, what will the following query return?

SELECT customers.name, orders.id FROM customers LEFT JOIN orders ON customers.id = orders.customer_id WHERE orders.id IS NULL;

AAll customers who have not placed any orders

BAll customers who have placed at least one order

CAll orders without a matching customer

DAll customers and their orders

Step-by-Step Solution

Solution:

Step 1: Analyze LEFT JOIN with WHERE condition
The LEFT JOIN returns all customers with matching orders or NULL if no order exists. The WHERE clause filters rows where orders.id is NULL, meaning no matching order.
Step 2: Interpret the result
This query returns customers who have no orders because orders.id is NULL for them.
Final Answer:
All customers who have not placed any orders -> Option A
Quick Check:
LEFT JOIN + WHERE orders.id IS NULL = customers without orders [OK]

Quick Trick: LEFT JOIN + WHERE right table column IS NULL finds missing matches [OK]

Common Mistakes:

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