# Aggregate functions
<a name="sql-functions-aggregated"></a>

 Aggregate functions are database operations that perform calculations across multiple rows of data to produce a single summarized result. These functions analyze data sets to return computed values like sums, averages, counts, or other statistical measures. 


|  **Function**  |  **Signature**  |  **Description**  | 
| --- | --- | --- | 
| `AVG` | AVG (expression) | Returns the average of a numerical expression. | 
| `COUNT` | COUNT (expression) | Returns the number of rows that match the given criteria. | 
| `MAX` | MAX (expression) | Returns the largest value of the selected expressions. | 
| `MIN` | MIN (expression) | Returns the smallest value of the selected expressions. | 
| `SUM` | SUM (expression) | Returns the sum of a numerical expression. | 
| `STDDEV` | STDDEV (expression) | Returns the sample standard deviation. | 
| `GROUP BY` | GROUP BY expression | Returns a row created by the grouping columns. | 
| `HAVING` | HAVING boolean-expression | Returns group rows filtered by `GROUP BY` clause. | 

Examples of all functions:


|  **Function**  |  **Example**  | 
| --- | --- | 
| AVG |  <pre>SELECT d.asset_id, d.property_id, AVG(d.int_value) FROM raw_time_series AS d</pre>  | 
| COUNT |  <pre>SELECT COUNT(d.int_value) FROM raw_time_series AS d</pre>  | 
| MAX |  <pre>SELECT MAX(d.int_value) FROM raw_time_series AS d</pre>  | 
| MIN |  <pre>SELECT MIN(d.int_value) FROM raw_time_series AS d</pre>  | 
| SUM |  <pre>SELECT SUM(d.int_value) FROM raw_time_series AS d</pre>  | 
| STDDEV |  <pre>SELECT STDDEV(d.int_value) FROM raw_time_series AS d</pre>  | 
|  [See the AWS documentation website for more details](http://docs.aws.amazon.com/iot-sitewise/latest/userguide/sql-functions-aggregated.html)  |  <pre>SELECT MAX(d.int_value) AS max_int_value, d.asset_id <br />FROM raw_time_series AS d <br />GROUP BY d.asset_id <br />HAVING MAX(d.int_value) > 5                      <br /></pre>  |