tsqlparser

tsqlparser

A T-SQL parser written in Go. Parses Microsoft SQL Server T-SQL syntax into an abstract syntax tree (AST).

Features

• Parses T-SQL DDL and DML statements
• Supports stored procedures, functions, triggers, and views
• Handles complex queries with CTEs, window functions, subqueries
• Full support for JOINs, PIVOT/UNPIVOT, MERGE, and set operations
• Control flow statements (IF/ELSE, WHILE, TRY/CATCH)
• Transaction handling
• XML and JSON operations
• 96% pass rate on a corpus of 201 real-world T-SQL samples

Installation

go get github.com/ha1tch/tsqlparser

Usage

package main

import (
    "fmt"
    "github.com/ha1tch/tsqlparser"
)

func main() {
    input := `SELECT CustomerID, Name FROM Customers WHERE Status = 'Active'`
    
    program, errors := tsqlparser.Parse(input)
    if len(errors) > 0 {
        for _, err := range errors {
            fmt.Println("Error:", err)
        }
        return
    }
    
    fmt.Println(program.String())
}

Supported Statements

DML

• SELECT (with all clauses, JOINs, subqueries, CTEs, window functions)
• INSERT (single row, multi-row, SELECT, EXEC, DEFAULT VALUES)
• UPDATE (with FROM, OUTPUT)
• DELETE (with FROM, OUTPUT)
• MERGE (all WHEN clauses)
• TRUNCATE TABLE

DDL

• CREATE/ALTER/DROP TABLE
• CREATE/ALTER/DROP INDEX
• CREATE/ALTER/DROP VIEW
• CREATE/ALTER/DROP PROCEDURE
• CREATE/ALTER/DROP FUNCTION
• CREATE/ALTER/DROP TRIGGER
• CREATE/ALTER/DROP DATABASE
• CREATE/ALTER/DROP SCHEMA

Control Flow

• IF/ELSE
• WHILE
• BEGIN/END
• TRY/CATCH
• GOTO
• RETURN
• BREAK/CONTINUE
• WAITFOR

Transactions

• BEGIN/COMMIT/ROLLBACK TRANSACTION
• SAVE TRANSACTION

Other

• DECLARE variables
• SET statements
• EXECUTE/EXEC
• Cursors (DECLARE, OPEN, FETCH, CLOSE, DEALLOCATE)
• GRANT/DENY/REVOKE
• BACKUP/RESTORE
• DBCC commands
• BULK INSERT

Project Structure

tsqlparser/
├── token/          # Token types and keywords
├── lexer/          # Lexical analysis
├── ast/            # Abstract syntax tree nodes
├── parser/         # Recursive descent parser
├── version/        # Version information package
├── testdata/       # 201 T-SQL sample files for integration testing
├── cmd/example/    # Example usage
├── tsqlparser.go   # Main API
├── VERSION         # Version number (single source of truth)
└── go.mod

Version

Access the library version programmatically:

import "github.com/ha1tch/tsqlparser/version"

fmt.Println(version.Version)  // "0.5.0"
fmt.Println(version.Full())   // "tsqlparser version 0.5.0"

Testing

Run all tests:

go test ./...

Run integration tests against the T-SQL corpus:

go test ./parser -run TestCorpusIntegration -v

Run a specific sample file:

go test ./parser -run TestCorpusSamples/001_error_handler -v

Run benchmarks:

go test ./parser -bench=.

Run corpus benchmarks:

go test ./parser -bench=Corpus -benchtime=1s

Performance

• Simple SELECT: ~23 μs
• Complex query with JOINs: ~34 μs
• Full corpus (201 files, 1.6 MB): ~27 MB/s throughput

License

Copyright (C) 2025-2026 haitch

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 3.

See https://www.gnu.org/licenses/gpl-3.0.html for the full license text.

Contact

h@ual.fi