Distinct

PRQL

SQL

SELECT
  DISTINCT department
FROM
  employees

This also works without a linebreak:

PRQL

from employees
select department
group department (take 1)

SQL

# youngest employee from each department
from employees
  sort age
  take 1
)

  SELECT
    *,
    ROW_NUMBER() OVER (
      PARTITION BY department
      ORDER BY
        age
    ) AS _expr_0
  FROM
    employees
)
SELECT
  *
FROM
  table_1 AS table_0
WHERE

Note that we can’t always compile to DISTINCT; when the columns in the aren’t all the available columns, we need to use a window function:

WITH table_1 AS (
  SELECT
    *,
    ROW_NUMBER() OVER (PARTITION BY first_name, last_name) AS _expr_0
  FROM
    employees
)
SELECT
  *
FROM
  table_1 AS table_0
WHERE
  _expr_0 <= 1

# youngest employee from each department
from employees
group department (
  sort age
)

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