PostgreSQL - GROUP BY clause - GeeksforGeeks

PostgreSQL - GROUP BY clause

Last Updated : 24 Oct, 2026

PostgreSQL GROUP BY clause divides rows into categories based on one or more column values, making it easier to calculate summary information for each category.

  • Creates separate result sets for each category.
  • Works with aggregate functions like COUNT(), SUM(), AVG(), MIN() and MAX().

Syntax

SELECT column_1, aggregate_function(column2)
FROM table_name
GROUP BY column_1;

Where:

  • GROUP BY: Groups rows with the same values into a single group.
  • aggregate_function(): Performs calculations such as COUNT(), SUM(), AVG(), MIN() or MAX() on each group.

Examples

Consider the following sales table for the examples below:

Screenshot-2026-10-01-094926

Example 1: Group Rows Without an Aggregate Function

Query:

SELECT region
FROM sales
GROUP BY region
ORDER BY region;

Output:

Screenshot-2026-07-28-115434
  • GROUP BY clause groups rows by the region column and returns one row for each unique region.

Example 2: Calculate Total sales for Each region

Query:

SELECT region,
       SUM(amount) AS total_sales
FROM sales
GROUP BY region
ORDER BY total_sales DESC;

Output:

Screenshot-2026-10-01-095457
  • GROUP BY clause groups the rows by region and the SUM() function calculates the total sales amount for each region.

Example 3: Count the Number of sales by Each sales_person

Query:

SELECT sales_person,
       COUNT(*) AS total_sales
FROM sales
GROUP BY sales_person
ORDER BY sales_person;

Output:

Screenshot-2026-10-01-095940
  • COUNT() function counts the number of sales made by each sales_person after grouping the rows by sales_person.

Example 4: Group by Multiple Columns

Query:

SELECT region,
       sales_person,
       SUM(amount) AS total_sales
FROM sales
GROUP BY region, sales_person
ORDER BY region;

Output:

Screenshot-2026-10-01-100003
  • GROUP BY clause groups rows based on both region and sales_person.
  • SUM() calculates the total sales for each group.
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