SQL Formatter

About SQL Formatter

Pretty-print long single-line SQL into clean, indented, multi-line form. Great for code review, debugging, and documentation.

Supported Dialects

Standard SQL, MySQL, PostgreSQL, SQLite, MS SQL (T-SQL), BigQuery and more - keywords and functions of each dialect are recognized correctly.

Privacy

All processing happens in your browser. You can safely format production-DB queries and sensitive SQL.

Dialect-specific differences to watch out for

• LIMIT vs TOP vs FETCH - MySQL and PostgreSQL use LIMIT 10; SQL Server uses SELECT TOP 10; Oracle and standard SQL use FETCH FIRST 10 ROWS ONLY. This is a common source of bugs when migrating between databases.
• String concatenation - The standard is ||; MySQL uses CONCAT(); SQL Server uses +. In MySQL, || is interpreted as OR, so relying on it produces completely wrong results.
• Date functions - NOW() in MySQL, CURRENT_TIMESTAMP in standard SQL, GETDATE() in SQL Server, CURRENT_DATETIME() in BigQuery. Always replace these when porting a query.
• Identifier quoting - MySQL uses backticks (`column`); standard SQL and PostgreSQL use double quotes ("column"); SQL Server uses brackets ([column]). Case-sensitivity rules differ as well.
• Boolean - PostgreSQL has a native BOOLEAN type; MySQL emulates it with TINYINT(1); Oracle uses NUMBER(1).
• RETURNING clause - PostgreSQL, SQLite 3.35+, and MariaDB support INSERT ... RETURNING *. MySQL 8 does not; SQL Server uses OUTPUT instead.

SQL anti-patterns - five you see all the time

• SELECT * - In production, always name the columns you actually need. Wildcards make schema changes risky and waste network bandwidth.
• Wrapping a column in a function inside WHERE - WHERE DATE(created_at) = '2026-05-05' prevents index use. Rewrite as a range: WHERE created_at >= '2026-05-05' AND created_at < '2026-04-21'.
• N+1 queries - Running a query inside a loop. Consolidate with a JOIN or an IN clause instead.
• Implicit type coercion - WHERE phone = 01012345678 (integer) vs '01012345678' (string). A type mismatch disables the index and can produce locale-dependent results.
• ORDER BY RAND() - Triggers a full table scan. On large tables use a sampling subquery or, in BigQuery, TABLESAMPLE.

Official references

• PostgreSQL SQL Commands - The official reference for the dialect closest to the SQL standard.
• MySQL Reference Manual - Full function and syntax documentation.
• BigQuery Standard SQL - Data warehouse dialect reference.
• T-SQL Reference (SQL Server) - Covers TOP, IDENTITY, OUTPUT, and other Microsoft extensions.
• SQLite SQL Syntax - Lightweight embedded database syntax reference.
• sql-formatter (open source) - The library powering this formatter.

When your queries return JSON columns, use the JSON Formatter & Converter to inspect the output. For HTML, CSS, or JS code formatting, see the HTMLㆍCSSㆍJS Formatter.

FAQ