Find Users Who Never Placed an Order

SQL

Technical Specification

Write a query to find all users that have no orders in orders table.

Input/Output Samples

Input:users and orders

Output:users without any orders

Optimal Logic Path

-- Option 1: LEFT JOIN
SELECT u.*
FROM users u
LEFT JOIN orders o ON o.user_id = u.id
WHERE o.id IS NULL;

Architectural Deep-Dive

Users with no matching order row will have NULL in joined columns, so we filter by that.