AVG¶

Computes the average (arithmetic mean) of all non-NULL values in a group.

Syntax¶

Parameters¶

AVG(expression): Calculates the average of all non-NULL values of expression in the group. NULL values are ignored.

Returns¶

Returns a DOUBLE representing the average of all non-NULL values. If all values are NULL or the input set is empty, returns NULL.

Examples¶

Setup¶

For these examples, assume we have a sales table:

CREATE TABLE sales(
    id BIGINT,
    product STRING,
    region STRING,
    amount BIGINT,
    PRIMARY KEY(id))

INSERT INTO sales VALUES
    (1, 'Widget', 'North', 100),
    (2, 'Widget', 'South', 150),
    (3, 'Gadget', 'North', 200),
    (4, 'Gadget', 'South', NULL),
    (5, 'Widget', 'North', 120)

AVG - Average All Values¶

Calculate the average of all amounts in the table:

SELECT AVG(amount) AS average_amount FROM sales

`average_amount`
`142.5`

Notice that the NULL value in row 4 is ignored, so the average is 570 / 4 = 142.5.

AVG with GROUP BY¶

Calculate average amounts per product:

SELECT product, AVG(amount) AS average_amount
FROM sales
GROUP BY product

`product`	`average_amount`
`"Widget"`	`123.33333333333333`
`"Gadget"`	`200.0`

Calculate average amounts per region:

SELECT region, AVG(amount) AS average_amount
FROM sales
GROUP BY region

`region`	`average_amount`
`"North"`	`140.0`
`"South"`	`150.0`

The South region average only includes the non-NULL value (150), ignoring the NULL from the Gadget sale.

Important Notes¶

Index Requirement: GROUP BY queries require an appropriate index to execute. See Indexes for details on creating indexes that support GROUP BY operations.