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MySQL Syntax Checker

Validate MySQL 5.7/8.x queries before you run them: backtick identifiers, LIMIT offset forms, ON DUPLICATE KEY UPDATE and MySQL-only functions are understood.

MySQL errors this catches, and how to fix them

  • Double-quoted identifiers. MySQL reads "name" as a string unless ANSI_QUOTES is on. Use backticks: `order`.
  • Reserved words as names. order, group, key, rank (8.0+) and lead must be quoted with backticks.
  • FULL OUTER JOIN. Not supported. Combine a LEFT JOIN and a RIGHT JOIN with UNION.
  • LIMIT inside IN subqueries. MySQL rejects IN (SELECT … LIMIT n). Wrap it in a derived table.
  • ONLY_FULL_GROUP_BY. Since 5.7 every selected column must be grouped or aggregated. That rule is a server setting, so a syntax checker passes the query but the server may reject it.

Need to move this query to another database? The SQL dialect converter rewrites it and lists every change. To make it readable first, use the SQL formatter.

Other dialects

PostgreSQL Syntax Checker · SQL Server Syntax Checker · SQLite Syntax Checker · MariaDB Syntax Checker · BigQuery SQL Validator · Snowflake SQL Validator · Redshift SQL Validator · All dialects

Questions

Is this MySQL syntax checker free and private?

Yes. The MySQL grammar is downloaded once and your SQL is parsed in the browser, so nothing is uploaded. Only the optional “Explain & fix with AI” button sends the failing statement to an AI model.

Does it check that my MySQL tables and columns exist?

No. It checks syntax only, because it never connects to your database. Valid statements list the tables and columns they reference so you can compare them yourself; EXPLAIN on a development database checks the names for real.

Which MySQL versions are covered?

The grammar comes from the open-source node-sql-parser project and targets current MySQL syntax. Very new features or vendor extensions can be flagged as errors even when the server accepts them; confirm those with the official MySQL documentation.

Why does MySQL reject double-quoted identifiers?

MySQL reads "name" as a string unless ANSI_QUOTES is on. Use backticks: `order`.

Why does MySQL reject reserved words as names?

order, group, key, rank (8.0+) and lead must be quoted with backticks.

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