Grafana 9.5.1, expression to add 2 queries from different datasources

  • What Grafana version and what operating system are you using?
    9.5.1 , on ubuntu

  • What are you trying to achieve?
    I have 2 datasources, 1 is prometheus, 2 is postgres
    I want to use expressiont o add 2 queries to show as 1 single metric
    using time series chart.

  • How are you trying to achieve it?
    I created a query from prometheus
    and another query from postgres, both can be shown correctly independently.
    Then I use expression to add them up
    but the new series is empty (while the original 2 raw queries are valid)