Postgres's lateral joins allow for quite the good eDSL
3 days ago
- #PostgreSQL
- #Rust
- #eDSL
- Lateral joins in PostgreSQL allow referencing columns from preceding FROM clauses in subqueries, enabling expressive query composition.
- Using lateral joins, query builders can offer composable, type-safe, and reusable query eDSLs while generating valid SQL automatically.
- The Haskell library Rel8 demonstrates building queries via lateral joins, similar constructs are being implemented in a Rust library called rust-rel8.
- This approach addresses limitations in ORMs and query builders, like poor composability and type safety, by leveraging the underlying SQL features directly.