Multiple Aggregation Projections in fluxql

InfluxDB 2
,
3

There are a few things they could do.
Union and pivot two streams:

  |> range(start: -1d)
  |> filter(fn: (r) => r._field == "temp")
temp_mean = data |> mean() |> set(key: "_field", as: "temp_mean")
num_points = data |> count |> set(key: "_field", as: "num_points")
union(tables: [temp_mean, num_points])
  |> pivot(rowKey:["_time"], columnKey: ["_field"], valueColumn: "_value")
  1. Use reduce to create a custom aggregate that does both at the same time:
data = from(bucket: "example-bucket")
  |> range(start: -1d)
  |> filter(fn: (r) => r._field == "temp")
  |> reduce(
    identity: {num_points: 0, sum:0.0, temp_mean:0.0}
    fn: (r) => ({
      num_points: accumulator.num_points + 1,
      sum: r._value + accumulator.sum,
      temp_mean: (accumulator.sum + r._value) / (float(v: num_points + 1))
    })
  )
  |> drop(columns: ["sum"])