Dialects

Dialects control how SQL is parsed and generated. The Transpiling page showed them in action. This page explains how they work under the hood and lists every supported dialect.

Class-based (recommended) ​

Pass dialect classes directly. No registration needed, fully tree-shakeable.

import { parse, transpile } from "sqlingo";
import { MySQL } from "sqlingo/mysql";
import { Postgres } from "sqlingo/postgres";

parse("SELECT 1", { read: MySQL });
transpile("SELECT 1", { read: MySQL, write: Postgres });

Each dialect is a separate import, so your bundler only ships the ones you use.

String-based (opt-in) ​

For apps that resolve dialects from config or user input, register them first with Dialect.register().

import { Dialect } from "sqlingo";
import { MySQL } from "sqlingo/mysql";
import { Postgres } from "sqlingo/postgres";

Dialect.register(MySQL, Postgres);

parse("SELECT 1", { read: "mysql" });

How dialects work ​

Each dialect is a class with three parts:

1. Tokenizer rules: how to break SQL into tokens (keywords, identifier quoting, escape sequences)

2. Parser overrides: dialect-specific syntax (MySQL backtick quoting, BigQuery struct syntax, etc.)

3. Generator transforms: how to map AST nodes to SQL (converting NVL to COALESCE, etc.)

When you pass { read: MySQL, write: Postgres }, sqlingo uses MySQL's tokenizer and parser to read the input, then Postgres's generator to write the output.

Supported dialects ​

32 SQL dialects, each importable as a standalone module for tree-shaking.