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bin_at()

Rounds values down to a fixed-size bin, with control over the bin's starting point.

Syntax

bin_at (value,bin_size,fixed_point)

Parameters

Name	Type	Required	Description
value	int, long, real, timespan, or datetime	✓	The value to round.
bin_size	int, long, real, or timespan	✓	The size of each bin.
fixed_point	int, long, real, timespan, or datetime	✓	A constant of the same type as value indicating one value of value, which is a fixed point for which `bin_at(fixed_point, bin_size, fixed_point) == fixed_point`.

If value is a timespan or datetime, then the bin_size must be a timespan.

Returns

The nearest multiple of bin_size below value, shifted so that fixed_point will be translated into itself.

Examples

Expression	Result	Comments
`bin_at(6.5, 2.5, 7)`	`4.5`
`bin_at(time(1h), 1d, 12h)`	`-12h`
`bin_at(datetime(2017-05-15 10:20:00.0), 1d, datetime(1970-01-01 12:00:00.0))`	`datetime(2017-05-14 12:00:00.0)`	All bins will be at noon
`bin_at(datetime(2017-05-17 10:20:00.0), 7d, datetime(2017-06-04 00:00:00.0))`	`datetime(2017-05-14 00:00:00.0)`	All bins will be on Sundays

In the following example, notice that the "fixed point" arg is returned as one of the bins and the other bins are aligned to it based on the bin_size. Also note that each datetime bin represents the starting time of that bin:

## Example

events    
    | project original_time
    | where original_time > ago(30d)    
    //--- USER Criteria He
    | summarize Hits=count() by bin_at(datetime(2023-06-15 10:20:00.0), 1d, datetime(1970-01-01 12:00:00.0))

Results