Difference Between sql-formatter and prettier-plugin-sql-cst

[grantwforsythe]

I know @nene has mentioned on several occasions that there are some fundamental problems with sql-formatter. I wanted to create a post that describes the main problems that will be addressed in prettier-plugin-sql-cst.

Some of the initial questions I have:

• Is this new package meant to be a replacement for this package?
• Should more development be allocated to the new project instead of trying to maintain this one?

[nene]

Is this new package meant to be a replacement for this package?

Mostly, but the implementation approach it takes is a much more labor-intensive one. Importantly, it needs a full SQL parser implementation of each dialect that it supports. And accordingly it only works when it's able to fully parse its input SQL. The upside of this is that the formatter can fully understand the language it's formatting and take advantage of it.

The sql-formatter library has a more heuristic approach. It essentially looks for some familiar tokens in the input text and tries to reorganize the whitespace between them. But it has a fairly limited understanding of the actual language structure, which leads to various bugs like not being able to distinguish when SET is part of UPDATE statement or some other language construct (e.g. ON DELETE SET NULL). The upside is that supporting a new dialect is largely a matter of a little configuration.

Should more development be allocated to the new project instead of trying to maintain this one?

That's what I've actually been doing. Though at the moment I don't really have much time to develop the new library, so I've pretty much limited myself to responding to the bug reports in this repository.

These two libraries will probably both go on existing for a long time though, because implementing support in the new lib for all the dialects that sql-formatter supports is such a grand undertaking.

[grantwforsythe]

What about prettier-plugin-sql?

[nene]

What about prettier-plugin-sql?

This library is just a lightweight wrapper around sql-formatter. It also has an option of using node-sql-parser for formatting, but that just serializes the query in one long line (plus that parser library is really buggy, I very much don't recommend it).