ARRAY_CUM_SUM

Description

Get the cumulative sum of an array (NULL values are skipped). If the array contains NULL values, then NULL is set at the same position in the result array.

Syntax

ARRAY_CUM_SUM(<arr>)

Parameters

Parameter	Description
<arr>	The array to calculate the cumulative sum from

Return Value

Returns an array. Special cases:

• NULL values in the array are skipped, and NULL is set at the same position in the result array.

Example

create table array_type_table(
    k1 INT, 
    k2 Array<int>
) 
duplicate key (k1) 
distributed by hash(k1) buckets 1 
properties(
    'replication_num' = '1'
);
insert into array_type_table values (0, []), 
(1, [NULL]), 
(2, [1, 2, 3, 4]), 
(3, [1, NULL, 3, NULL, 5]);
select k2, array_cum_sum(k2) from array_type_table;

+-----------------------+-----------------------+
| k2                    | array_cum_sum(`k2`)   |
+-----------------------+-----------------------+
| []                    | []                    |
| [NULL]                | [NULL]                |
| [1, 2, 3, 4]          | [1, 3, 6, 10]         |
| [1, NULL, 3, NULL, 5] | [1, NULL, 4, NULL, 9] |
+-----------------------+-----------------------+