User-defined functions and aggregates
Cassandra 2.2 introduced user-defined functions (UDF) and aggregates support. You access UDF and aggregate values in your queries like regular columns:
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const query = 'SELECT avg(salary) as salary FROM employees';
client.execute(query, function (err, result) {
assert.ifError(err);
const row = result.first();
console.log('Average salary %d', row.salary);
});
The driver also exposes UDFs and aggregates metadata information, for example let’s see how to retrieve the metadata information of a UDF named iif, that takes a boolean and int parameter.
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client.metadata.getFunction('ks1', 'iif', ['boolean', 'int'], function (err, udf) {
if (err) return console.error(err);
console.log('Function metadata %j', udf);
});