Relational is more than SQL(fauna.com)

  t1 [LEFT/RIGHT/INNER] JOIN t2 USING col

  t1 [LEFT/RIGHT/INNER] JOIN t2 ON (t1.col == t2.col)

    ```sh
    > prqlc compile <<EOF
    let get = path obj -> s"""{obj} -> {path}"""
    let getstr = path obj -> s"""{obj} ->> {path}"""
    let extract = obj path -> s"""json_extract({obj}, {path})"""
    
    from [{data='{"duck": [1, 2, 3]}'}]
    select { data | get '$.duck[0]', data | getstr '$.duck[1]', extract data '$.duck[2]' }
    EOF
    WITH table_0 AS (
      SELECT
        '{"duck": [1, 2, 3]}' AS data
    )
    SELECT
      data -> '$.duck[0]',
      data ->> '$.duck[1]',
      json_extract(data, '$.duck[2]')
    FROM
      table_0
    
    -- Generated by PRQL compiler version:0.9.4 (https://prql-lang.org)
    ```

    ```sh
    > prqlc compile <<EOF - | duckdb
    let get = path obj -> s"""{obj} -> {path}"""
    let getstr = path obj -> s"""{obj} ->> {path}"""
    let extract = obj path -> s"""json_extract({obj}, {path})"""
    
    from [{data='{"duck": [1, 2, 3]}'}]
    select { data | get '$.duck[0]', data | getstr '$.duck[1]', extract data '$.duck[2]'}
    EOF
    ┌───────────────────────┬──────────────────────────┬───────────────────────────────────┐
    │ "data" -> '$.duck[0]' │ ("data" ->> '$.duck[1]') │ json_extract("data", '$.duck[2]') │
    │         json          │         varchar          │               json                │
    ├───────────────────────┼──────────────────────────┼───────────────────────────────────┤
    │ 1                     │ 2                        │ 3                                 │
    └───────────────────────┴──────────────────────────┴───────────────────────────────────┘
    ```

    -- for each manager, find their employee with the highest salary
    > select
    >   manager.name,
    >   (select employee.name
    >    from employee
    >    where employee.manager = manager.name
    >    order by employee.salary desc
    >    limit 1)
    > from manager;
     name  | name
    -------+------
     alice | bob