SQL dialect
PostgreSQL SQL Parser for Java and .NET
General SQL Parser (GSP) parses PostgreSQL with a dedicated, hand-tuned grammar — full AST access, offline syntax validation, formatting, rewriting, and column-level data lineage , including complete procedural SQL support. One commercial SDK, 38 dialects, Java and .NET.
Example
PostgreSQL SQL that GSP parses
CREATE FUNCTION add_tax(amount numeric) RETURNS numeric AS $$
BEGIN
RETURN amount * 1.08;
END;
$$ LANGUAGE plpgsql;Parse it in Java
import gudusoft.gsqlparser.*;
TGSqlParser parser = new TGSqlParser(EDbVendor.dbvpostgresql);
parser.sqltext = sql; // the PostgreSQL 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 PostgreSQL
- Dollar-quoted PL/pgSQL bodies
- RETURNING on DML
- Recursive CTEs
- COPY statements
- MERGE ... DO NOTHING (PG 15)
- Procedural SQL: Dollar-quoted PL/pgSQL function bodies parsed to statement level via TCreateFunctionStmt (not treated as opaque strings)
Beyond parsing, the same AST powers table/column extraction, validation, formatting, and column-level lineage for PostgreSQL.
Actively maintained
Recent PostgreSQL parser updates
- 2026-06-12 [PostgreSQL] Support EXCLUDE WHERE and constraint attributes
- 2026-06-12 [PostgreSQL] Fix NOT DEFERRABLE token corruption
- 2026-05-17 [PostgreSQL, DuckDB] MERGE WHEN MATCHED THEN DO NOTHING (PG 15+)
Full history in the release notes.
Go deeper
PostgreSQL resources
- PostgreSQL syntax reference — dialect documentation
- PostgreSQL keyword compatibility — every keyword, and whether it can be an identifier
- Java quick start — Maven/Gradle setup and first parse
- C# quick start — NuGet setup for .NET
Common questions
Does GSP parse PostgreSQL stored procedures and procedural SQL?
Yes. GSP parses Dollar-quoted PL/pgSQL function bodies parsed to statement level via TCreateFunctionStmt (not treated as opaque strings) into a full AST — procedure bodies become real statement trees you can traverse, not opaque text blocks. This is what makes lineage and impact analysis work inside procedural code.
Do I need a PostgreSQL database connection to validate SQL?
No. GSP validates PostgreSQL syntax completely offline. You get error line and column positions, the offending token, and a hint — with no server, driver, or credentials involved.
How complete is the PostgreSQL grammar?
GSP uses a dedicated hand-tuned grammar for PostgreSQL — not a generic SQL grammar with flags. The parser recognizes 613 PostgreSQL keywords and knows which 574 of them can also be used as identifiers, which is exactly the kind of edge case that breaks generic parsers.
Can I use the PostgreSQL parser from C# / .NET?
Yes. The .NET edition (NuGet package gudusoft.gsqlparser, .NET Standard 2.0) exposes the same API surface as the Java edition, so every PostgreSQL parsing feature on this page works in C# and VB.NET.
Can GSP extract column-level lineage from PostgreSQL SQL?
Yes. The built-in DataFlowAnalyzer produces column-level lineage, impact analysis, and call graphs from PostgreSQL scripts — it is the engine behind Gudu SQLFlow and the lineage integrations for DataHub and OpenMetadata.