SQL Formatter
Format and beautify SQL queries
Format SQL so it stays readable in code review, incidents, and migrations
SQL pasted from an ORM log, a query plan, or a chat message is almost always one giant unreadable line. Reading it during an incident at 2am is exactly when you cannot afford ambiguity. This formatter prettifies SQL for major dialects, aligns clauses and joins, normalizes keyword casing, and keeps comments. Use it to make queries reviewable before committing migrations, debugging slow plans, or sharing snippets with teammates.
- Paste your SQL query, statement, or stored procedure into the input panel.
- Choose the dialect that matches your database. Standard SQL works for most cases, but PostgreSQL, MySQL, T-SQL, and BigQuery have specific keywords.
- Pick uppercase or lowercase keyword formatting, then format. Compare the output to the original to confirm semantics did not change.
- Copy the formatted SQL into your migration file, code review, or runbook.
Formatting is the start of SQL review, not the end
Formatting is only the first pass in SQL review. A readable statement makes joins, predicates, grouping, and nested queries easier to inspect, but it does not reveal whether parameters are safely bound, whether an index can support the filter, or whether the result cardinality is correct.
After formatting, inspect execution plans with the target database, test representative data volumes, and verify that untrusted values are passed as parameters rather than concatenated into the query.
What SQL injection is and how formatting helps review it
SQL injection happens when user input is allowed to alter query structure instead of being treated purely as data. The root cause is usually string concatenation rather than parameterized queries, prepared statements, ORM bindings, or safe query builders.
This matters on a formatter page because formatted SQL makes query structure easier to inspect. You can see more clearly whether a value lands in a literal, a column name, an `ORDER BY`, or an entire condition fragment. Formatting helps review, while real injection defense comes from parameterization, allowlists, and least privilege.
Practical SQL optimization without folklore
Good SQL optimization advice starts with execution plans, not slogans. Reduce scanned rows early, align indexes with `where`, `join`, and `order by`, avoid wrapping indexed columns in functions that defeat index usage, and be cautious with `select *` on large result sets.
Formatted SQL helps because a clean layout makes logical blocks easier to inspect. Extra subqueries, repeated sorts, accidental cross joins, redundant predicates, and oversized `IN` lists are easier to spot once the statement is readable. Use the readable output as the starting point for an evidence-based review with the database execution plan.
Best use cases
- Cleaning ORM-generated SQL before adding it to a migration or runbook.
- Reformatting copied queries from production logs during incident analysis.
- Aligning keywords and indentation in long SELECT statements for clearer review.
Common mistakes to avoid
- Formatters can occasionally trip on dialect-specific syntax such as window functions, lateral joins, or PL/pgSQL blocks. Verify before running the formatted version.
- Reformatting a query never changes its plan, so do not expect performance improvements from prettifying alone.
- Long IN lists are a smell. The formatter will indent them, but the right fix is usually a JOIN or a temp table.
How this tool works
- Implementation
- sql-formatter with the dialect selected on the page
- Data path
- Input is processed in the current browser tab. Tool input is not submitted to a DevHelper Tools application server.
- Independent check
- Parse or execute only in a safe target database environment; formatting does not validate syntax, safety, or query performance.
Verify before production use
A successful conversion or generated snippet is not proof that it matches your runtime. Check the output against an independent implementation, test one known edge case, and record the environment or standard version you validated.
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FAQ
Which dialects are supported?
Standard SQL, PostgreSQL, MySQL, MariaDB, SQLite, T-SQL (SQL Server), BigQuery, Snowflake, Redshift, and a few more, courtesy of sql-formatter.
Will formatting change the query result?
No. Formatting only changes whitespace, indentation, and keyword case. The semantics and execution plan remain identical.
Can it format DDL and stored procedures?
Mostly yes for DDL. Stored procedures with embedded procedural blocks (PL/pgSQL, T-SQL) may need manual touch-ups around BEGIN/END structures.