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row_cumsum()

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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