Difference Between 2 values in a query?

InfluxDB 2
10

Add this line to the very beginning:

import "math"

and this function to the very end (after the difference() function):

|> map(fn: (r) => ({r with _value: math.abs(x: r._value)}))

First = from(bucket: "test")
  |> range(start: -1d)
  |> filter(fn: (r) => r["_measurement"] == "Energy")
  |> filter(fn: (r) => r["_field"] == "Unrest_totals")
  |> first()
  |> yield(name: "First")

Last = from(bucket: "test")
  |> range(start: -1d)
  |> filter(fn: (r) => r["_measurement"] == "Energy")
  |> filter(fn: (r) => r["_field"] == "Unrest_Totals")
  |> last()
  |> yield(name: "Last")

union(tables: [First, Last])
|> difference()