```console
❯ tree data/
data/
├── c
│   ├── 1.json
│   └── 2.json
└── j
    ├── 1.json
    └── 2.json
```

```console
> SELECT . FROM c
{"id":2,"j_id":3}
{"foo":"bar","id":1,"j_id":1}

> SELECT id FROM c
{"c.id":2}
{"c.id":1}

> SELECT c.id, j.id, is_j FROM c LEFT JOIN j ON j.id == c.j_id
{"c.id":2,"is_j":null,"j.id":null}
{"c.id":1,"is_j":true,"j.id":1}

> SELECT c.id, j.id FROM c RIGHT JOIN j ON j.id == c.j_id
{"c.id":null,"j.id":2}
{"c.id":1,"j.id":1}

> SELECT c.id, j.id FROM c FULL JOIN j ON j.id == c.j_id
{"c.id":2,"j.id":null}
{"c.id":1,"j.id":1}
{"c.id":null,"j.id":2}
```