{"success": true, "results": {"a": …, "b": …, "c": …}}

{"success": true, "results": {"b": …}}

$ jq 'del(select(.results.b | not))'
{"success": true, "results": {"a": …, "b": …, "c": …}}
# removes nothing from "results"

$ jq 'with_entries(select(.key == "success" or .key == "results.b"))
{"success": true}
# nested comparison not understood; returns only "success"