SQLGlot

Overview

SQLGlot is a pure-Python library for parsing SQL into an abstract syntax tree (AST), analyzing or rewriting that tree, and generating SQL back out in a specified dialect. Its most common use is transpilation: converting a query written for one database's SQL dialect into the equivalent syntax for another, which is useful when migrating between databases, building cross-dialect tooling, or writing dialect-agnostic query generators. Beyond transpilation, SQLGlot also includes a query optimizer and a lightweight, in-memory SQL execution engine.

Basic usage

Copy code
import sqlglot

sql = "SELECT EPOCH_MS(1700000000000) AS ts"
transpiled = sqlglot.transpile(sql, read="duckdb", write="hive")[0]
# 'SELECT FROM_UNIXTIME(1700000000000 / POW(10, 3)) AS ts'

You can also parse without converting dialects, walk the resulting expression tree, and programmatically build SQL from Python objects rather than string concatenation.

SQLGlot and DuckDB

SQLGlot has first-class support for the DuckDB SQL dialect, including many of DuckDB's distinctive extensions such as QUALIFY, list and struct literals, and DuckDB-specific function names, which means it can transpile queries written in other dialects into idiomatic DuckDB SQL, and vice versa. This makes it a common building block for tools that need to run the same logical query across multiple engines — for example, a BI tool or semantic layer that wants to support both a cloud warehouse and a local DuckDB instance without maintaining separate handwritten SQL for each. SQLGlot's DuckDB dialect support does not require an actual DuckDB installation; it operates purely on SQL text and is a separate, independently maintained open-source project rather than being part of DuckDB itself.