SQL Formatter
Quickly and easily format and beautify SQL queries. Paste your SQL Query below.
Advertisement
Advertisement
SQL Formatting Best Practices
Well-formatted SQL is easier to read, debug, and maintain — especially in team environments. Consistent formatting also helps query analyzers understand the intent of complex queries.
SQL Style Guide Conventions
- Keywords uppercase: SELECT, FROM, WHERE, JOIN, GROUP BY
- One clause per line: SELECT on one line, FROM on next, WHERE on next
- Indent subqueries: each nesting level adds 2–4 spaces
- Aliases are lowercase:
users AS u
Common SQL Performance Patterns to Avoid
SELECT *: always specify only needed columns- Functions in WHERE clause: prevents index use — use range comparison instead
- N+1 queries: fetching related records in a loop — use JOINs or IN clauses
- Missing indexes on JOIN and WHERE columns — run EXPLAIN to identify full table scans
What is the difference between MySQL and PostgreSQL syntax?
PostgreSQL uses double quotes for identifiers; MySQL uses backticks. PostgreSQL's ILIKE for case-insensitive matching; MySQL's LIKE is case-insensitive by default. PostgreSQL has richer data types (JSONB, arrays) and stricter type checking. For new projects, PostgreSQL is generally preferred for its standards compliance.
How do I make a slow SQL query faster?
Start with EXPLAIN/EXPLAIN ANALYZE to see the execution plan. Look for "Seq Scan" on large tables (add an index). Common fixes: add indexes on WHERE, JOIN, and ORDER BY columns; avoid SELECT *; avoid functions on indexed columns in WHERE clauses; use LIMIT when you only need a few rows.