How to query multiple tables from different buckets with inner join?

[nasserHHDE]

Describe the issue
In InfluxDB 3.4, attempting to perform an INNER JOIN on tables that originate from different buckets fails. This limits the ability to perform cross-bucket analysis, which is especially important for users with data logically separated by bucket (e.g., metrics and events).

Steps to reproduce

Create two buckets: bucketA and bucketB

Write data into each (e.g., cpu data in bucketA, and alerts in bucketB)

Attempt the following SQL-like query:

SELECT *
FROM bucket_1.cpu a
INNER JOIN bucket_2.alerts b
ON a.host = b.host AND a.time = b.time

Query fails or returns errors.

Expected behavior
The join should return rows where host and time match across the two tables, even if they come from different buckets.

Actual behavior

The query either fails with a syntax or execution error
Query execution failed: API response error: "query error: error while planning query: Error during planning: table 'public.bucket_1.cpu' not found"

No clear documentation that this use case is unsupported

Environment

InfluxDB version: 3.4

Query language: SQL from both Explorer UI and HTTP API

[hiltontj]

Hello @nasserHHDE, it is currently not possible to query across databases (buckets) in InfluxDB v3.

[philjb]

Please see also this suggestion in our community slack to join data from separate queries in your query client application as Trevor says, sql joins across databases is not possible within v3 currently.