sequelts VS pgtyped

You can use these template literal types + infer to build an entire SQL parser. I did a POC that infers SQL query types by parsing the SQL query on a type level:

https://github.com/nikeee/sequelts

However, building this parser is pretty cumbersome and supporting multiple SQL dialects would be lots of pain. While I'm not a fan of query builders per se, Kysely pretty much covers everything that my POC tried to cover (except that 0 runtime overhead). However, you get the option to use different DBMs in tests than in production (pg in prod, sqlite in tests), which is a huge benefit for a lot of people. sequelts was designed to work with sqlite only. And it's not a hack.

The only thing I can imagine where this would be useful is when you don't have control about what DB is being used, for example, when building a product that should be compatible with Postgres and MariaDB (and each is getting used). However, in the age of containerization, this isn't a big problem any more.

In some ORMs, I need to create types that the result of a query containing JOINs is mapped to. Others don't support them _at all_. In TypeORM, there is a query builder which forces you to put in _some_ SQL for things like "WHERE a in (b, c)".

I created a proof of concept of a different approach: Just embrace SQL and provide static typing based on the query. The return type of a query is whatever that thing is that the query returns in the context of the database schema. It's possible to do in TypeScript, by parsing the SQL query at development time:

https://github.com/nikeee/sequelts

One benefit is that it does not need any runtime code, as it's just a type layer over SQL. You don't have to rely on some type-metadata that TypeScript emits. That's why it also works with JavaScript only.

I don't like ORMs that use runtime types either. Most of the time, I want to write raw SQL.

So as an experiment, I created a library that statically types raw SQL:

https://github.com/nikeee/sequelts

The idea is to parse the SQL queries using TS's type system. The parsed query is combined with the database schema and therefore, we know what type the query will return.

This is especially useful due to TS's structural type system.

There is an implementation of SQL that operates on a table shaped type, entirely at type level. For your amusement: https://github.com/codemix/ts-sql

There are a bunch of more practical takes that codegen types from your database and generate types for your queries, eg: https://github.com/adelsz/pgtyped

To me the second approach seems much more pragmatic because you don’t need to run a SQL parser in a fairly potato interpreter on every build

ORMs suck, but raw SQL embedded in your code sucks too.

This might be good time to plug my TypeScript non-ORM: https://jawj.github.io/zapatos/.

I should say I also like what I've seen of https://kysely.dev/ and https://pgtyped.dev/.

Thank you for suggestions they helped me finding what I was looking for. I will either pick kysely or https://pgtyped.dev/, but first I will do some tests. Thanks!

Cool. How does this compare to SafeQL, PgTyped, and Postgres language server ?

I would instead rely on code generation like https://github.com/adelsz/pgtyped, because the embedded type-safe SQL will never fully cover all the features of vanilla SQL, for example Common Table Expression (CTE), window functions etc.

There's pgtyped, which I believe does almost the same as sqlc

https://github.com/adelsz/pgtyped

For Postgres there is https://github.com/adelsz/pgtyped, sounds pretty much like what you describe?

Avoiding the cost of learning EDSL that many Haskell DB libraries provide, I found out that only postgresql-typed and postgresql-simple allow to write only raw SQL queries easily. As I extensively use pgtyped for production Node.js application, I am thinking about using postgresql-typed. While I could find many resources for postgresql-simple, the same cannot be said try for postgresql-typed.

I would highly recommend trying out pgTyped if you want typesafe queries with postgres. It's fantastic!