JSON vs SQL - pro's and con's

I'm working on a project that manages coding projects and i'm looking for the best database to use for it.

The app stores many types of information about the working project like general data, task list, project state, some parts of the data base will have a history branch..

and i was wondering what are the pro's and con's for using an SQL based data base vs. using a JSON formatted database.

As i see it (correct me if im wrong) the main benefit of SQL is the ability to relate records from one list to records from another list with unique ID's where as the drawback is that i can only store data in tables (which is not always logically correct - when task's and user list are related to the project more and to one another more than two task list are connected to one another)

And JSON's main benefit is to use complex objects that i can organize as i want to suit my app logic so that the data will be placed all in one place and relate to the relevant project.

Thanks