SQL GROUP BY and HAVING, Explained with Examples

Updated 2026-06-03

GROUP BY turns many rows into one row per group, computing aggregates like SUM or COUNT for each. HAVING then filters those groups. Together they answer "per category" questions.

▶ Open the GROUP BY + HAVING example in SQL Visualizer

GROUP BY: one row per group

To get total revenue per genre, group the movies by genre and sum within each group:

SELECT genre, SUM(revenue) AS total_revenue
FROM movies
GROUP BY genre
ORDER BY total_revenue DESC

Aggregate functions

• COUNT(*) — number of rows in the group
• SUM(x) / AVG(x) — total / average of a column
• MIN(x) / MAX(x) — smallest / largest value

HAVING: filter the groups

A WHERE clause filters rows before grouping and cannot see aggregates. To filter on an aggregate — say, keep only genres whose total revenue exceeds 1000 — use HAVING, which runs after grouping:

SELECT genre, SUM(revenue) AS total_revenue
FROM movies
GROUP BY genre
HAVING SUM(revenue) > 1000
ORDER BY total_revenue DESC

For the precise difference between the two filters, read WHERE vs HAVING.

Where it sits in the query

GROUP BY runs after WHERE and before SELECT; HAVING sits between them. See the complete SQL execution order.

▶ Open the GROUP BY + HAVING example in SQL Visualizer