PromQL
A [ query language ] to pull data from the [ Prometheus ] [ time series DB ] .
A query is more akin to a Array programming language statement than to a typical [ SQL ] query.
aggregation_operation(data_column{tag="value"}) + aggretation_operation(other_data_column{tag="value"})
Usual queries
Get a column or 0 if null (doesn't work for full time-series graphs)
0
data_column{} OR on() vector(0)
See
https://nklya.medium.com/promql-how-to-return-0-instead-of-no-data-9e49f7ccb80d
Articles
PromQL cheat sheet
Url
https://promlabs.com/promql-cheat-sheet/