🐥 Pretty-printing SQL using Elixir

When you want to pretty-print SQL statements using Elixir, the sql_fmt library is what you should be looking at.

Install it by adding this to your dependencies:

{:sql_fmt, "~> 0.3.0"}

To use it, you can do something like this:

iex(1)> {:ok, formatted_sql} = SqlFmt.format_query("select * from businesses where id in ('c6f5c5f1-a1fc-4c9a-91f7-6aa40f1e233d', 'f339d4ce-96b6-4440-a541-28a0fb611139');")
{:ok, "SELECT\n  *\nFROM\n  businesses\nWHERE\n  id IN (\n    'c6f5c5f1-a1fc-4c9a-91f7-6aa40f1e233d',\n    'f339d4ce-96b6-4440-a541-28a0fb611139'\n  );"}

iex(2)> IO.puts(formatted_sql)
SELECT
  *
FROM
  businesses
WHERE
  id IN (
    'c6f5c5f1-a1fc-4c9a-91f7-6aa40f1e233d',
    'f339d4ce-96b6-4440-a541-28a0fb611139'
  );
:ok

SqlFmt also provides you with the ~SQL sigil that can be used to format SQL via Mix Formatter plugin. To set up the Mix Formatter plugin, simply install this package and add update your .formatter.exs file as follows:

[
  plugins: [SqlFmt.MixFormatter],
  inputs: ["**/*.sql"],
  # ...
]

With this configuration, the SqlFmt Mix Format plugin will now format all ~SQL sigils and all files ending in .sql. This can be particularly useful in Ecto migrations where you have large execute statements and you want to make sure that your code is readable. Check out the SqlFmt.MixFormatter module docs for more information.