What is JSON?
The format the web runs on. Nested objects and arrays, real types, and a syntax small enough to fit on a postcard. It maps badly onto a grid, which is why converting deeply nested JSON to a spreadsheet always involves losing something.
What is SQL?
Not a file format so much as a language, but a file of INSERT statements is how data has always been moved into a database. Every engine will run one, and it's the least surprising thing to hand to a database that already exists.