Hasan Savran shows how the JSON_PATH_EXISTS() function works in SQL Server:
Schemas can easily change if you save your data in JSON format. It is very easy to add or remove properties from JSON documents. When the data model changes quickly, you might need to worry about if the property you are looking for exists in the documents. If the path you are looking for does not exist in some documents, you need to handle the exception in some way. JSON_PATH_EXISTS comes to your help in situations like that. It tests whether a specified path exists in the input JSON.
Read on for the syntax and examples of use.