Oracle 12c JSON Nested Object Retrieval

I have a JSON data set that I need to work with in Oracle 12c. It contains nested objects and I need to extract specific values from these objects.

select json_query('{ "validationResults": { "errorMessages": [], "status": "PASS" }, "clearanceStatus": "CLEARED", "clearedInvoice": "PD94bWwgdmVyc" }','$.validationResults') as aaa from dual;

Key objectives and requirements:
- Retrieve data from nested objects: The data set contains nested objects and I need a solution that can delve into these structures and retrieve the desired values.
- Aggregation of values: Once the data is extracted, I need it to be aggregated in a specific way.

Skills and experience sought:
- Proficiency in Oracle 12c: You should have a strong background in using Oracle 12c for data processing and manipulation.
- Experience with JSON data: You should be experienced in working with JSON formatted data, particularly nested objects.
- Aggregation expertise: Prior experience with aggregating data will be a plus.

Please provide details of your relevant experience, and outline how you would approach this task.