SQL Formatter

Understanding the Basics

SQL (Structured Query Language) is the standard language for relational database management, used by systems including PostgreSQL, MySQL, SQLite, SQL Server, Oracle, BigQuery, Snowflake, and Redshift. Complex SQL queries — particularly those involving multiple JOINs, nested subqueries, window functions, CTEs (Common Table Expressions), and CASE expressions — grow into long, difficult-to-read strings when written without intentional formatting. Query strings extracted from ORM debug logs, database audit trails, or code obfuscated by minification are especially challenging to analyze. SQL formatting applies consistent capitalization (SQL keywords like SELECT, FROM, WHERE in uppercase by convention), consistent indentation for nested subqueries, aligned column lists in SELECT clauses, and line breaks before each major clause keyword. Well-formatted SQL dramatically reduces the time needed to understand query logic, identify Cartesian products, spot missing join conditions, and optimize execution plans. Our formatter uses the sql-formatter library, which supports 12 SQL dialects including ANSI SQL, MySQL, PostgreSQL, T-SQL (SQL Server), PL/SQL (Oracle), and BigQuery Standard SQL.

How to Use the Tool

1. Paste your SQL query (or multiple queries separated by semicolons) into the input editor.
2. Select the SQL dialect from the dropdown: ANSI SQL, MySQL, PostgreSQL, SQL Server, Oracle, BigQuery, or others.
3. The formatter capitalizes reserved keywords, applies indentation to subqueries and CASE expressions, and aligns SELECT column lists.
4. Click "Format" — the formatted query appears in the output editor with syntax highlighting.
5. Copy or download the formatted SQL for code review, documentation, or query optimization analysis.

Key Features & Specifications

• Supports 12 SQL dialects: ANSI, MySQL, PostgreSQL, SQL Server T-SQL, Oracle PL/SQL, BigQuery, Snowflake, Spark SQL, and more
• Uppercase keyword normalization (SELECT, FROM, WHERE, JOIN, ON, GROUP BY, ORDER BY)
• Proper indentation for subqueries, CTEs, CASE expressions, and nested JOINs
• Handles stored procedures, DML (INSERT/UPDATE/DELETE), DDL (CREATE/ALTER), and CTEs
• Configurable indentation width and keyword case (uppercase/lowercase/preserve)

Frequently Asked Questions (FAQ)

Q:Should SQL keywords be uppercase or lowercase?

The SQL standard is case-insensitive for keywords. The convention of uppercase SQL keywords (SELECT, FROM, WHERE) originated in an era when terminals did not highlight syntax, making uppercase keywords visually distinct from lowercase table and column names. Modern editors with syntax highlighting make this less critical, but uppercase keywords remain the dominant convention in documentation and professional contexts.

Q:Does the formatter change query semantics or execution plans?

No. SQL formatting only adds whitespace and normalizes letter case for keywords — it does not alter the query's logical meaning, optimization hints, or execution strategy in any way. The database optimizer processes the formatted query identically to the original.

Q:Can I format SQL embedded in Python, Java, or JavaScript strings?

This tool formats raw SQL text. If your SQL is embedded in a programming language string (with concatenation, f-strings, or template literals), you need to extract the pure SQL text first, format it, then re-embed it. For ongoing automated formatting of SQL in code files, use sqlfluff as a linter and formatter in your build pipeline.