prettier-plugin-sql-cst

Prettier plugin SQL-CST

A Prettier plugin for SQL that uses sql-parser-cst and the actual Prettier formatting algorithm.

Like Prettier for JavaScript, this plugin formats SQL expressions differently depending on their length. A short SQL query will be formatted on a single line:

SELECT a, b, c FROM tbl WHERE x > 10

A longer query, will get each clause printed on a separate line:

SELECT id, client.name, client.priority
FROM client
WHERE client.id IN (12, 18, 121)

An even longer one gets the contents of each clause indented:

SELECT
  client.id,
  client.name AS client_name,
  organization.name AS org_name,
  count(order.id) AS nr_of_orders
FROM
  client
  LEFT JOIN organization ON client.organization_id = organization.id
  LEFT JOIN order ON order.client_id = client.id
WHERE
  client.status = 'active'
  AND client.id IN (28, 214, 457)
  AND order.status IN ('active', 'pending', 'processing')
GROUP BY client.id
ORDER BY client.name
LIMIT 100

Getting started

Install it as any other Prettier plugin:

npm install --save-dev prettier prettier-plugin-sql-cst

Then use it on SQL files though Prettier command line tool or Prettier extension for your editor of choice.

Configuration

The standard Prettier options apply. There's also one SQL-specific option:

API Option	Default	Description
printWidth	80	Same as in Prettier
tabWidth	2	Same as in Prettier
useTabs	false	Same as in Prettier
sqlKeywordCase	preserve	Converts SQL keywords to upper or lower case.
sqlAliasAs	preserve	Uses AS keyword in aliases either always or never.

Limitations and development status

Currently this plugin only supports subset of SQLite syntax. Formatting of the following SQL statements is fully implemented:

• SELECT
• UPDATE
• INSERT
• DELETE
• CREATE TABLE

Unlike Prettier for JavaScript, this plugin currently preserves all the syntax elements. For example it does not add/remove paratheses or modify the case of keywords (by default). It only manipulates whitespace.

This will likely change in the future, with the goal of being more opinionated. Some possibilities:

• capitalize all keywords
• ensure all alias definitions use the AS keyword.
• ensure consistent use of quotes (e.g. always quote keywords)
• eliminate redundant parenthesis.

The exact formatting style is also very much still in flux. The overall goal is to have no options to configure different styles, but rather to develop one opinionated style of formatting SQL.