F-strings

F-strings are a readable approach to building new strings from existing strings & variables.

PRQL

from employees
select full_name = f"{first_name} {last_name}"

SQL

SELECT
  CONCAT(first_name, ' ', last_name) AS full_name
FROM
  employees

This can be much easier to read for longer strings, relative to the SQL approach:

PRQL

from web
select url = f"http{tls}://www.{domain}.{tld}/{page}"

SQL

SELECT
  CONCAT(
    'http',
    tls,
    '://www.',
    domain,
    '.',
    tld,
    '/',
    page
  ) AS url
FROM
  web

Note that currently interpolations can only contain plain variable names and not whole expression like Python, so this won’t work:

PRQL

from tracks
select length_str = f"{length_seconds / 60} minutes"

Error

Error:
   ╭─[:2:37]
   │
 2 │ select length_str = f"{length_seconds / 60} minutes"
   │                                     ┬
   │                                     ╰── unexpected end of input while parsing interpolated string
───╯

Roadmap

In the future, f-strings may incorporate string formatting such as datetimes, numbers, and padding. If there’s a feature that would be helpful, please post an issue.