summarize

Groups rows by one or more key columns and computes aggregations over each group.

Spec

... | summarize <aggregation> [, ...] [by <group_column> [, ...]]

Parameters

aggregation   - An aggregate function call, optionally aliased (e.g. total = count()).
group_column  - A column or expression to group by.

Return Value

One row per unique combination of group columns. Output contains the group columns
and the aggregation result columns.

Example

datatable(Service:string, Latency:int64)
[
    "web", 10,
    "web", 20,
    "api", 5,
    "api", 15
]
| summarize avg(Latency), count() by Service

Service	avg_Latency	count
web	15	2
api	10	2

Summarize without grouping returns a single row:

range val from 1 to 5 step 1
| summarize sum(val), count()

sum_val	count
15	5