SQL Practice Problem #010 - Label orders with CASE

Problem

Task

Return each order id and a size label: High for orders of 100 or more, otherwise Standard.

Schema

orders(id, customer_id, total_amount, ordered_at)

Input

id	customer_id	total_amount	ordered_at
101	1	58.5	2026-03-02
102	2	104	2026-03-07

Output

id	order_size
101	Standard
102	High

Answer

Show Answer and Explanation

SELECT id,
  CASE
    WHEN total_amount >= 100 THEN 'High'
    ELSE 'Standard'
  END AS order_size
FROM orders;

CASE creates a derived value based on conditions. The WHEN branch handles orders of 100 or more, and ELSE handles every remaining order.

Forgetting END before the alias.
Using double quotes for string values in a MySQL setup where single quotes are expected.
Leaving out ELSE and returning NULL for standard orders.

Concepts

CASE Conditional Expressions Aliases SELECT Derived Column

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