SQL Formatter

An SQL Formatter transforms messy, unformatted SQL queries into clean, readable, well-indented code. SQL queries are the foundation of data retrieval and manipulation in relational databases. As queries grow in complexity with multiple joins, subqueries, and conditional logic, they quickly become difficult to read and maintain without proper formatting.

The formatter parses SQL statements and applies consistent indentation rules. Keywords like SELECT, FROM, WHERE, JOIN, and ORDER BY are placed at the beginning of lines. Column lists are indented beneath their parent clause. Nested subqueries receive additional indentation levels. The result is a query whose structure is immediately visible through its formatting.

Database administrators format queries before sharing them with team members for review. A well-formatted query communicates its intent clearly. Code reviews of SQL are more productive when the query structure is easy to follow. Poorly formatted queries hide logical errors in walls of unbroken text.

Developers use SQL formatting to debug queries that are not returning expected results. Formatting reveals the structure of joins, the logic of WHERE conditions, and the nesting of subqueries. An incorrectly placed parentheses or a misunderstanding of operator precedence becomes obvious when the query is properly formatted.

The formatter supports multiple SQL dialects including MySQL, PostgreSQL, Microsoft SQL Server, Oracle, and SQLite. Each dialect has unique syntax elements and reserved words. The formatter recognizes these dialect-specific features and handles them appropriately. PL/SQL blocks, T-SQL procedures, and PostgreSQL functions are all formatted correctly within their respective dialects.

User-defined functions and stored procedures receive special formatting treatment. The BEGIN and END blocks are indented to show the procedure structure. Parameter lists are formatted with consistent spacing. Exception handling blocks are indented to show the error handling flow within the code.

Comment preservation ensures that inline and block comments are not lost during formatting. Single-line comments starting with double hyphen and block comments enclosed in slash-star are retained in their original positions. Leading comments that describe the query purpose are preserved at the top of the formatted output.

Keyword case options allow converting all SQL keywords to uppercase, lowercase, or capitalizing the first letter. Consistent keyword case improves readability, and different teams have different conventions. The formatter applies the chosen case consistently across the entire query for a professional, uniform appearance.