Recalculate the _value column

This example uses NOAA water sample data.

Recalculate the _value column without creating a new one. Use the with operator in map() to overwrite the existing _value column.

The following query: - Uses filter() to filter the average_temperature measurement. - Uses map() to convert Fahrenheit temperature values into Celsius.

from(bucket: "noaa")
  |> filter(fn: (r) => r._measurement == "average_temperature")
  |> map(fn: (r) => ({r with _value: (float(v: r._value) - 32.0) * 5.0 / 9.0} ))

queries