How to check if a tag exists in a measurement using flux?

Question

How to check if a specific tag exists in a measurement using flux language? My influxdb version is 2.0.

Could you please post your efforts in your question(what you tried) that's highly encouraged on SO, thank you. — RavinderSingh13, May 02 '21 at 16:25
I have the same question too, so i might expand it if this is ok, rather than asking another... — David van rijn, May 24 '21 at 10:59

score 3 · Answer 1 · answered Aug 19 '21 at 15:38

3

simple you need to add a filter for the tag name you need to filter to your flux query. let's say the tag name is "tag_name":

|> filter(fn: (r) => exists r.tag_name)

this will filter any undefined or "unset" tag.

answered Aug 19 '21 at 15:38

Hany Zekry

31
2

score 2 · Answer 2 · answered May 24 '21 at 11:15

(answering for my usecase, since no details were provided)

TL;DR: use the exists operator.

Imagine a dataset which has this old tag, which we don't care about anymore, and we want to filter out those records when archiving:


option task = {
  name: "15min_archive",
  every: 1w,
}

from(bucket: "mybucket")
 |> range(start: - duration(v: int(v: task.every) * 2))
// this:
 |> filter(fn: (r) => (exists r["stupidOldTag"] ) == false )
 |> aggregateWindow(every: 15m, fn: mean)
// ...

note: the ==false because not is apparently not a thing yet.

How to check if a tag exists in a measurement using flux?

2 Answers2