I want to fetch the “_time” of the last inserted measurement.
With the help of top Limit() with multiple optional fields (limit limits each field separately) I learned about funcion v1.fieldsAsCols(), which corresponds to schema.fieldsAsCols() in v2.
The issue is that I receive loads of tables as result without fieldsAsCols() and all fields when using this function, while I still only need the value of the _time column.
import "influxdata/influxdb/schema" from(bucket: "dsm") |> range(start: v.timeRangeStart, stop: v.timeRangeStop) |> filter(fn: (r) => r["equipment_id_electricity"] == "39") |> last() |> schema.fieldsAsCols() |> limit(n: 1) |> keep(columns: ["_time"])
This query looks processing intensive for the simple task.
Is there a way to optimize the query and get only one result (1 row and 1 column)?
PS Thumbs up for “Data Explorer” that its function [ Inject ] button also automagically creates the import line for influxdata/influxdb/schema