MIN() and MAX() Across Groups

Overview

MIN() and MAX() return the smallest and largest value of a column. With GROUP BY they reveal the range inside each bucket — here, the lowest and highest priced product per category in the store.

The Query

Step-by-Step Breakdown

1. MIN(price) / MAX(price) — the category's price floor and ceiling.
2. MAX(price) - MIN(price) — a derived price_spread column.
3. GROUP BY category — ranges computed per category, not globally.

Variations

Find earliest and latest movie release per genre:

Common Mistakes

• Confusing with LIMIT. MIN(price) returns the value; ORDER BY price LIMIT 1 returns the row — use the aggregate when you only need the number.
• NULL handling. MIN/MAX ignore NULLs, which can hide missing data.
• Non-grouped column in SELECT. SELECT name, MIN(price) without grouping name is invalid.