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#0317
Join Orders to Customer Names
EasySQL15 min10 XP
Problem
Return order_id, customer name, and amount for orders with known customers.
Why This Matters
SQL interviews usually test whether you can turn a business question into the right rows, grouping level, join type, and edge-case behavior.
Schema
orders(order_id INTEGER, customer_id INTEGER, amount INTEGER); customers(customer_id INTEGER, name TEXT)
Examples
Example 1
Inputone order has unknown customer_id 3
Outputonly orders 10 and 11
INNER JOIN keeps rows with matching customer records.
Constraints
- Return only the requested columns.
- Use deterministic ORDER BY when multiple rows are returned.
- Assume SQLite-compatible SQL unless the prompt states otherwise.
CodeSQL
Visible browser tests run here when available.
Testcases1 visible / 3 hidden categories
Core SQL case
Inputone order has unknown customer_id 3
Expected[[10,"Asha",50],[11,"Ben",30]]
INNER JOIN keeps rows with matching customer records.
Hidden Test Categories
Empty or missing matchesDuplicate rows or tiesNULL values where the pattern commonly breaks