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Reserved words used as aliases cause a crash #801
Description
Input data
SELECT set.foo FROM settings AS setHere's a more complex example (the error is a bit different):
SELECT id AS srvid,
CASE WHEN id = $1 THEN $2
ELSE
COALESCE(alias, hostname || $3 || port)
END AS alias,
CASE WHEN id = $4 THEN $5 ELSE hostname END as hostname,
CASE WHEN id = $6 THEN $7 ELSE port END AS port,
CASE WHEN id = $8 THEN set.setting
ELSE s.version::text
END AS version
FROM public.powa_servers s
LEFT JOIN pg_settings set ON set.name = $9 AND s.id = $10Usage
- How are you calling / using the library?
import { formatDialect, postgresql } from "sql-formatter";
formatDialect(value, { dialect: postgresql })Tested in the online demo as well.
-
What SQL language(s) does this apply to?
PostgreSQL, but the first example fails with any dialect with the same error -
Which SQL Formatter version are you using?
15.4.6
Activity
nene commentedon Nov 14, 2024
Thanks for reporting.
Although this error occurs with other dialects, it's more of a PostgreSQL-specific issue as most SQL dialects don't allow reserved keywords to be used as aliases. PostgreSQL also only allows some, like the following won't work:
However this syntax is valid in DB2, where one can even write:
Isn't SQL a wonderful language :D
Usually I would recommend checking out prettier-plugin-sql-cst, which does a much better job at formatting PostgreSQL than this library, but turns out that the same issue is also present in there. Though my hopes of fixing this issue in there are much higher than fixing it in here.
[-][FORMATTING] Reserved words can't be used as aliases[/-][+]Reserved words used as aliases cause a crash[/+]Treat a reserved word after AS as an alias
Address review: narrow isAsKeyword, move tests to shared helpers
nene commentedon Sep 23, 2026
This has now been improved in 15.9.0 release. Thing should be better now if you use
ASkeyword to declare aliases. Without theAS, there will still be problems though.