The example uses JSON_KEYS to get the key names of a JSON object. No depth is specified, so the entire depth is searched and the keys at all levels are returned.
SELECT * from JSON_KEYS ( ON (SELECT json_data FROM json_table)) AS json_data;
Result:
KEYS ---- “coord” “coord”.”lon” “coord”.”lat” “sys” “sys”.”country” “sys”.”sunrise” “sys”.”sunset” “weather” “weather”[0].”id” “weather”[0].”main” “weather”[0].”description” “weather”[0].”icon” “base” “main” “main”.”temp” “main”.”humidity” “main”.”pressure” “main”.”temp_min” “main”.”temp_max” “wind” “wind”.”speed” “wind”.”deg” “clouds” “clouds”.”all” “dt” “id” “name” “cod”