row_cumsum()

Applies to: ✅ Microsoft Fabric ✅ Azure Data Explorer ✅ Azure Monitor ✅ Microsoft Sentinel

Calculates the cumulative sum of a column in a serialized row set.

Syntax

row_cumsum( term [, restart] )

Learn more about syntax conventions.

Parameters

Name	Type	Required	Description
term	int, long, or real	✔️	The expression indicating the value to be summed.
restart	bool		Indicates when the accumulation operation should be restarted, or set back to 0. It can be used to indicate partitions in the data.

Returns

The function returns the cumulative sum of its argument.

Examples

The following example shows how to calculate the cumulative sum of the first few even integers.

Run the query

datatable (a:long) [
    1, 2, 3, 4, 5, 6, 7, 8, 9, 10
]
| where a%2==0
| serialize cs=row_cumsum(a)

a	cs
2	2
4	6
6	12
8	20
10	30

This example shows how to calculate the cumulative sum (here, of salary) when the data is partitioned (here, by name):

Run the query

datatable (name:string, month:int, salary:long)
[
    "Alice", 1, 1000,
    "Bob",   1, 1000,
    "Alice", 2, 2000,
    "Bob",   2, 1950,
    "Alice", 3, 1400,
    "Bob",   3, 1450,
]
| order by name asc, month asc
| extend total=row_cumsum(salary, name != prev(name))

name	month	salary	total
Alice	1	1000	1000
Alice	2	2000	3000
Alice	3	1400	4400
Bob	1	1000	1000
Bob	2	1950	2950
Bob	3	1450	4400