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(<agg_function>, <arr>)
| Parameter | Description |
|---|---|
<agg_function> | The name of an aggregate function which should be a constant string |
<arr> | Any number of array type columns as the parameters of the aggregation function. |
Examples
SELECT
REDUCE('max', [ 1, 2, 3, 6 ]) AS res;
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 res;
Returns: 2.5