Prometheus Query - Group by values and return a count

Question

I have a metric that returns a few unique values for each timeseries. (This is from Prometheus Blackbox Exporter). See example below

How can I group these by value and return a count. The following is the expected outcome

{status="400"}      1
{status="0"}        0
{status="200"}      2

Answer 1

Use the following PromQL:

count_values("status", probe_http_status_code)

More info in Prometheus documentation here.