SQL Optimizer

A lightweight SQL optimizer built in Python that parses SQL queries into an Abstract Syntax Tree (AST), converts them to a logical plan, applies basic query optimizations, and generates optimized SQL. Inspired by SQLGlot, this project is modular, educational, and extensible.

✨ Features

• Custom SQL parser (recursive descent) for SELECT queries
• Abstract Syntax Tree (AST) representation of SQL
• Logical plan generation from AST
• Basic optimization rules (e.g., predicate pushdown, projection pruning)
• SQL code generation from optimized logical plan
• CLI interface to parse and optimize SQL from file or stdin

Supported SQL Constructs

• Supported SQL Constructs
• SELECT, FROM, WHERE, JOIN (INNER, LEFT, RIGHT, FULL)
• GROUP BY, ORDER BY, LIMIT
• Table/column aliases
• Binary expressions (=, !=, <, >, <=, >=)
• Boolean logic (AND, OR)

Requirements

  - Python 3.7+

Future Enhancements

• Cost-based optimization
• Subquery flattening
• Transpile between SQL dialects
• Expression simplification (constant folding)