SQL Formatter

Dialect matters

SQL is a standard and also 30 dialects. Each vendor extended it: PostgreSQL added ::type casts, MySQL added backticks, BigQuery added EXCEPT(...), Snowflake added LATERAL FLATTEN. A dialect-unaware formatter mangles these or treats them as syntax errors.

Pick the dialect matching your target database. The formatter preserves dialect-specific syntax instead of flagging it.

Keyword case conventions

• UPPER (default): SELECT, FROM, WHERE. Oldest convention, most common in documentation and DBA tooling.
• lower: select, from, where. Modern convention in many application codebases (SQLAlchemy, Prisma docs).
• preserve: leave as-is. Use when a style guide forbids auto-rewriting.

What the formatter will and won't do

Does:

• Insert newlines at clause boundaries (SELECT, FROM, WHERE, JOIN, GROUP BY, ORDER BY)
• Align column lists, indent subqueries
• Normalize whitespace, strip trailing whitespace
• Preserve comments (both -- and /* */)
• Respect dialect-specific syntax

Does not:

• Execute the query
• Validate referenced tables/columns exist
• Optimize or rewrite the query
• Send your SQL anywhere: it runs entirely in your browser

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