REDUCE

Applies an aggregate function on the elements of the array and returns its result. The name of the aggregation function is passed as a string in single quotes - for example: 'max', 'sum'.

Syntax

REDUCE(<function>, <array>)

Parameters

Parameter	Description	Supported input types
`<function>`	The name of an aggregation function in the form of a quoted string.	Any aggregation function
`<array>`	The array to aggregate.	`ARRAY`

Return Types

Same as the element data type of the input array

Examples

SELECT
	REDUCE('max', [ 1, 2, 3, 6 ]) AS levels;

Returns: 6

When using aggregation functions that take a constant as a parameter, the parameter should be specified after the function name in parentheses. This example below uses REDUCE with the APPROX_PERCENTILE function, which requires a percentile as a parameter.

SELECT
	REDUCE('approx_percentile(0.3)', [ 1, 2, 3, 4, 5, 6 ]) AS levels;

Returns: 2.5