Reference material for AVG
Calculates the average of an expression.
Parameter | Description | Supported input types |
---|---|---|
<value> | The expression used to calculate the average | Any numeric type |
Valid values for the expression include column names or functions that return a column name (or columns) that contain numeric values.
The AVG()
aggregation function ignores rows with NULL
values. For example, an AVG
from 3 rows containing 1
, 2
, and NULL
returns 1.5
because the NULL
row is not counted. To calculate an average that includes NULL
, use SUM(COLUMN)/COUNT(*)
.
NUMERIC
if the input is type INTEGER
, BIGINT
or NUMERIC
DOUBLE PRECISION
if the input is type REAL
or DOUBLE PRECISION
Applying AVG
to REAL and DOUBLE PRECISION is subject to floating point arithmetic accuracy limitations and its resulting error.
This error may add up when aggregating multiple values.
The order of operations while computing the aggregate is non-deterministic. This can lead to varying total floating point error when running a query multiple times. If this is not acceptable for your use-case, aggregate on NUMERIC data instead.
The example below uses the following table LevelPoints
. This table includes the maximum points a player can score at each level of the game:
levels | maxpoints |
---|---|
1 | 50 |
2 | 100 |
3 | 150 |
4 | 200 |
5 | 250 |
Use the query below to find the average of the maxpoints
value.
Returns:
AverageMaxPoints |
---|
150 |