Amazon Redshift will no longer support the creation of new Python UDFs starting Patch 198. Existing Python UDFs will continue to function until June 30, 2026. For more information, see the [ blog post ](https://aws.amazon.com/blogs/big-data/amazon-redshift-python-user-defined-functions-will-reach-end-of-support-after-june-30-2026/). 

# Aggregate functions
<a name="c_Aggregate_Functions"></a>

**Topics**
+ [ANY\$1VALUE function](r_ANY_VALUE.md)
+ [APPROXIMATE PERCENTILE\$1DISC function](r_APPROXIMATE_PERCENTILE_DISC.md)
+ [AVG function](r_AVG.md)
+ [COUNT function](r_COUNT.md)
+ [LISTAGG function](r_LISTAGG.md)
+ [MAX function](r_MAX.md)
+ [MEDIAN function](r_MEDIAN.md)
+ [MIN function](r_MIN.md)
+ [PERCENTILE\$1CONT function](r_PERCENTILE_CONT.md)
+ [STDDEV\$1SAMP and STDDEV\$1POP functions](r_STDDEV_functions.md)
+ [SUM function](r_SUM.md)
+ [VAR\$1SAMP and VAR\$1POP functions](r_VARIANCE_functions.md)

Aggregate functions compute a single result value from a set of input values. 

SELECT statements using aggregate functions can include two optional clauses: GROUP BY and HAVING. The syntax for these clauses is as follows (using the COUNT function as an example): 

```
SELECT count (*) expression FROM table_reference
WHERE condition [GROUP BY expression ] [ HAVING condition]
```

The GROUP BY clause aggregates and groups results by the unique values in a specified column or columns. The HAVING clause restricts the results returned to rows where a particular aggregate condition is true, such as count (\$1) > 1. The HAVING clause is used in the same way as WHERE to restrict rows based on the value of a column. For an example of these additional clauses, see the [COUNT](r_COUNT.md).

Aggregate functions don't accept nested aggregate functions or window functions as arguments.