bin_at()

Rounds values down to a fixed-size "bin", with control over the bin's starting point. (See also bin function.)

Syntax

bin_at (Expression, BinSize, FixedPoint)

Arguments

• Expression: A scalar expression of a numeric type (including datetime and timespan) indicating the value to round.
• BinSize: A scalar constant of a numeric type or timespan (for a datetime or timespan Expression) indicating the size of each bin.
• FixedPoint: A scalar constant of the same type as Expression indicating one value of *Expression, which is a "fixed point" (that is, a value fixed_point for which bin_at(fixed_point, bin_size, fixed_point) == fixed_point.)

Returns

The nearest multiple of BinSize below Expression, shifted so that FixedPoint 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:

datatable(Date:datetime, Num:int)[
datetime(2018-02-24T15:14),3,
datetime(2018-02-23T16:14),4,
datetime(2018-02-26T15:14),5]
| summarize sum(Num) by bin_at(Date, 1d, datetime(2018-02-24 15:14:00.0000000)) 

Date	sum_Num
2018-02-23 15:14:00.0000000	4
2018-02-24 15:14:00.0000000	3
2018-02-26 15:14:00.0000000	5