SqlBuildingBlocks

Project Status

Component	Status
AnsiSQL grammar	Production-ready — SQL-89 + FETCH FIRST, 86+ negative tests per dialect
MySQL grammar	Production-ready — backticks, LIMIT/OFFSET, INTERVAL, ON DUPLICATE KEY UPDATE
PostgreSQL grammar	In development (stub — do not use in production)
SQL Server grammar	In development (stub — do not use in production)
Query engine	Beta — SELECT with CTEs (recursive + non-recursive), JOINs, window functions, aggregates, UNION/INTERSECT/EXCEPT, ORDER BY, GROUP BY/HAVING

Overview

SqlBuildingBlocks is an extensible open-source library for parsing SQL into manageable, logical classes tailored to different database technologies. It is built upon Irony's SQLGrammar example and leverages the Factory and Strategy patterns for customization of SQL parsing across multiple databases.

How It Works

SqlBuildingBlocks breaks down SQL into fundamental "building blocks" — NonTerminal classes, each handling a specific part of the SQL language. These NonTerminal classes use a factory pattern to create logical classes that represent SQL elements.

Query Engine

The QueryEngine class provides in-memory SQL execution. It accepts an ITableDataProvider (or IAllTableDataProvider for multi-table queries) and a parsed SqlSelectDefinition, and returns a VirtualDataTable of result rows.

Supported SELECT features:

• Simple projections, column aliases, SELECT *
• FROM table, INNER/LEFT/RIGHT/FULL OUTER JOIN
• WHERE clause with full predicate support (comparisons, IS NULL, LIKE, IN, BETWEEN, logical operators)
• GROUP BY + HAVING (aggregate predicates)
• ORDER BY with ASC/DESC and NULLS FIRST/NULLS LAST
• DISTINCT
• Aggregate functions: COUNT, SUM, AVG, MIN, MAX (including COUNT(DISTINCT col))
• Window functions: ROW_NUMBER, RANK, DENSE_RANK, LAG, LEAD, NTILE, FIRST_VALUE, LAST_VALUE, NTH_VALUE; ROWS BETWEEN frames; RANGE BETWEEN INTERVAL frames (DateTime ORDER BY)
• WITH (non-recursive CTE) and WITH RECURSIVE CTE; configurable depth limit via QueryEngineOptions.MaxRecursionDepth (default 100)
• UNION, UNION ALL, INTERSECT, EXCEPT
• Derived tables in FROM and JOIN positions
• SQL Server TOP N
• DBNull / three-valued logic in all predicates

Not yet supported (throws NotSupportedException): correlated subqueries, EXISTS, ROLLUP/CUBE/GROUPING SETS, GROUP BY ROLLUP, DML execution (INSERT/UPDATE/DELETE are parse-only).

// Parse
var grammar = new AnsiSqlGrammar();
var parser = new Parser(grammar);
var parseTree = parser.Parse("SELECT * FROM Orders WHERE Amount > 100");

// Resolve
var resolver = new SelectReferenceResolver(selectDef, connectionProvider, schemaProvider, functionProvider);
resolver.ResolveTablesDatabase();
resolver.ResolveReferences();

// Execute
var engine = new QueryEngine(tableDataProvider, selectDef);
var result = engine.QueryAsDataTable();

Project Objectives

• Extensibility: Specialized grammars for each database technology, extending a shared AnsiSQL base.
• Usability: Represent complex SQL grammar as manageable, logical classes.
• Testability: Strong unit-testing framework — 1279 passing tests across five NuGet packages.

Roadmap

• PostgreSQL grammar — dialect extensions beyond the current stub
• SQL Server grammar — dialect extensions beyond the current stub
• Correlated subquery execution
• GROUP BY ROLLUP / CUBE / GROUPING SETS execution

Contributing

We're open to contributions from the community. Please refer to our contributing guidelines for more information.

License

This project is licensed under the terms of the MIT license. For more information, please see the LICENSE file.

Installation

Install via NuGet. All five packages publish at the same version on every merge to main.

Package Name	Release (NuGet)
SqlBuildingBlocks.Core
SqlBuildingBlocks.Grammars.AnsiSQL
SqlBuildingBlocks.Grammars.MySQL
SqlBuildingBlocks.Grammars.PostgreSQL
SqlBuildingBlocks.Grammars.SQLServer

Contact

For any inquiries or issues, please open a GitHub issue.