DuckDB SQL Parser for Java and .NET

Example

DuckDB SQL that GSP parses

SELECT * FROM cities
PIVOT (SUM(population) FOR year IN (2000, 2010, 2020));

Parse it in Java

import gudusoft.gsqlparser.*;

TGSqlParser parser = new TGSqlParser(EDbVendor.dbvduckdb);
parser.sqltext = sql; // the DuckDB SQL above
if (parser.parse() == 0) {
    System.out.println(parser.sqlstatements.size() + " statement(s) parsed");
} else {
    System.out.println(parser.getErrormessage());
}

The .NET edition exposes the same API in C# — see the C# quick start.

Coverage

What GSP handles in DuckDB

• PIVOT/UNPIVOT statements
• QUALIFY clause
• Lambda and list comprehension
• Struct/map/list literals
• FROM-first syntax and GROUP BY ALL

Beyond parsing, the same AST powers table/column extraction, validation, formatting, and column-level lineage for DuckDB.

Actively maintained

Recent DuckDB parser updates

• 2026-05-17 [PostgreSQL, DuckDB] MERGE WHEN MATCHED THEN DO NOTHING (PG 15+)
• 2026-03-31 [DuckDB] Comprehensive dialect support: PIVOT/UNPIVOT, MACRO, lambdas, QUALIFY, ASOF JOIN, and more

Full history in the release notes.