DuckDB MSSQL Extension

A DuckDB extension for connecting to Microsoft SQL Server databases using native TDS protocol - no ODBC, JDBC, or external drivers required.

📈 Community Extension Downloads

📊 Interactive chart — queried live in your browser with DuckDB-Wasm.

Regenerated weekly and served from GitHub Pages, so it stays current without a commit. Counts are a Cloudflare estimate of INSTALL mssql FROM community events, aggregated across DuckDB versions and platforms. Source: DuckDB Community Extensions download metrics.

Experimental: This extension is under active development. APIs and behavior may change between releases. We welcome contributions, bug reports, and testing feedback!

Documentation

Full documentation lives at hugr-lab.github.io/mssql-extension — connections and authentication (SQL, Azure AD / Entra ID, Kerberos, Windows SSPI), catalog integration, query pushdown, bulk loading over BCP, DML, transactions, the complete settings reference, and performance tuning.

Quick pointers:

Getting Started	install, ATTACH, first queries
Connections & Auth	connection strings, secrets, Azure AD, Kerberos
Writing Data	COPY (bulk load), CTAS, INSERT/UPDATE/DELETE
Backup Files	describe a .bak without SQL Server
Settings Reference	every mssql_* setting with defaults
Troubleshooting	common errors and limitations
Articles	Medium deep dives on design and performance

Contributor docs stay in the repository: DATAMODEL.md (layered architecture), docs/ (internals), docs/TESTING.md, CLAUDE.md (development guidelines).

This is the beginning of the README. Read the rest at the original. Read the full README ↗