| # User-defined functions and aggregates |
| |
| Cassandra 2.2 introduced [user-defined functions](https://issues.apache.org/jira/browse/CASSANDRA-7395) (UDF) and |
| aggregates support. You access UDF and aggregate values in your queries like regular columns: |
| |
| ```javascript |
| const query = 'SELECT avg(salary) as salary FROM employees'; |
| client.execute(query) |
| .then(function (result) { |
| const row = result.first(); |
| console.log('Average salary %d', row.salary); |
| }); |
| ``` |
| |
| The driver also exposes [UDFs and aggregates metadata information](/api/module.metadata/), for example let's see how to retrieve the metadata |
| information of a UDF named iif, that takes a boolean and int parameter. |
| |
| ```javascript |
| client.metadata.getFunction('ks1', 'iif', ['boolean', 'int']) |
| .then(function (err, udf) { |
| console.log('Function metadata %j', udf); |
| }); |
| ``` |
| |
