Categories:: Query Syntax

GROUP BY¶

Groups rows with the same group-by-item expressions and computes aggregate functions for the resulting group. A GROUP BY expression can be a column name, a number referencing a position in the SELECT list, or a general expression.

Extensions:: GROUP BY CUBE , GROUP BY GROUPING SETS , GROUP BY ROLLUP

Syntax¶

SELECT ...
FROM ...
[ ... ]
GROUP BY groupItem [ , groupItem> [ , ... ] ]
[ ... ]

Where:

groupItem ::= { <column_alias> | <position> | <expr> }

column_alias: Column alias appearing in the query block’s SELECT list.
position: Position of an expression in the SELECT list.
expr: Any expression on tables in the current scope.

Examples¶

This example shows the gross revenue per product, grouped by product_id:

-- Create the sales table and insert some rows.
CREATE TABLE sales (product_ID INTEGER, retail_price REAL,
                    quantity INTEGER, city VARCHAR, state VARCHAR);
INSERT INTO sales (product_id, retail_price, quantity, city, state) VALUES
     (1, 2.00,  1, 'SF', 'CA'),
     (1, 2.00,  2, 'SJ', 'CA'),
     (2, 5.00,  4, 'SF', 'CA'),
     (2, 5.00,  8, 'SJ', 'CA'),
     (2, 5.00, 16, 'Miami', 'FL'),
     (2, 5.00, 32, 'Orlando', 'FL'),
     (2, 5.00, 64, 'SJ', 'PR');

-- Show the gross revenue, grouped by product_id.
-- In other words, show the total amount of money received for
-- selling each product.
SELECT product_ID, SUM(retail_price * quantity) AS gross_revenue
  FROM sales
  GROUP BY product_ID;

Output:

+------------+---------------+
| PRODUCT_ID | GROSS_REVENUE |
+============+===============+
|          1 |          6    |
+------------+---------------+
|          2 |        620    |
+------------+---------------+

This example builds on the previous example, showing the net profit per product, grouped by product_id:

-- Create the products table and insert some rows.
CREATE TABLE products (product_ID INTEGER, wholesale_price REAL);
INSERT INTO products (product_ID, wholesale_price) VALUES (1, 1.00);
INSERT INTO products (product_ID, wholesale_price) VALUES (2, 2.00);

-- Show the net profit on each product.
SELECT p.product_ID, SUM((s.retail_price - p.wholesale_price) * s.quantity) AS profit
  FROM products AS p, sales AS s
  WHERE s.product_ID = p.product_ID
  GROUP BY p.product_ID;

Output:

+------------+--------+
| PRODUCT_ID | PROFIT |
+============+========+
|          1 |      3 |
+------------+--------+
|          2 |    372 |
+------------+--------+

You can group by multiple columns:

SELECT State, City, SUM(retail_price * quantity) AS gross_revenue
 FROM sales
 GROUP BY State, City;

Output:

+-------+---------+---------------+
| STATE |   CITY  | GROSS REVENUE |
+=======+=========+===============+
|   CA  | SF      |            22 |
+-------+---------+---------------+
|   CA  | SJ      |            44 |
+-------+---------+---------------+
|   FL  | Miami   |            80 |
+-------+---------+---------------+
|   FL  | Orlando |           160 |
+-------+---------+---------------+
|   PR  | SJ      |           320 |
+-------+---------+---------------+