SQL dialects

Application code imports sql from one selected grammar package. That package—not the neutral AST or compiler—owns SQL syntax, built-ins, coercions, nullability, version gates, and diagnostics.

Grammar	Stable language range	Driver boundary
PostgreSQL	Majors 14–18	Application-owned pg; optional adapter at @typed-sql/postgres/pg
MySQL	8.4 and 9.7 LTS series	Application-owned mysql2; optional adapter at @typed-sql/mysql/mysql2
SQLite	3.39.0–3.53.4 complete baseline	Injected connection or optional built-in node:sqlite adapter

These three grammar packages are on the stable package track. A stable range is not the same thing as the exact versions exercised by the repository. Each dialect page lists both, including non-blocking future-version canaries.

How support is classified

• Exact means executable evidence proves row types, ordered parameters, diagnostics, and relevant semantics for that feature.
• Conservative means missing or ambiguous evidence preserves unknown.
• Unsupported means the grammar recognizes that the feature is unavailable and fails closed.
• Out of scope means the feature belongs to another grammar or is deliberately not modeled.

Review the generated grammar support matrix for individual features.

Driver independence

Installing a grammar does not install a database driver. Driver-specific imports are separate public entrypoints and are loaded only when selected. You may keep direct driver execution, create a typed-sql adapter, or adapt an existing pool.

Runtime decoding and compile-time inference use the same type policy. If the application changes its driver parsers or codecs, configure a matching policy rather than asserting a narrower result type.

Unknown versions and capabilities

An unrecognized future server or SQLite library is not assumed compatible. Missing version, mode, compile-option, extension, or catalog evidence produces a diagnostic or conservative result. Consult Compatibility for the tested Node, TypeScript, driver, and database matrix.