Free SQL Syntax Checker & Validator
Check and validate your SQL query for potential issues.
Check and validate your SQL query for potential issues.
SQL query to check: (currently only PostgreSQL is fully supported)
The SQL Validator is a free online tool that checks your SQL code for syntax errors and helps you write cleaner, more reliable queries. Paste in a query, select your database type and version, and the Validator parses your code the same way a real database would - flagging mistakes like missing commas, mismatched parentheses, unclosed quotes, invalid keywords, and malformed expressions before you ever run the query against a live system.
PostgreSQL is fully supported across versions 7 through 18, meaning the Validator uses PostgreSQL's own grammar to catch version-specific issues. The Validator also offers basic support for MySQL, Oracle, MariaDB, SQLite, SQL Server, ClickHouse, MongoDB, OpenSearch, Snowflake, BigQuery, and Elasticsearch.
The tool is free, requires no signup, and is useful for developers writing queries by hand, data analysts working in unfamiliar dialects, students learning SQL, and teams reviewing each other's code before it reaches production.
The Validator catches the full range of syntax mistakes that prevent SQL from parsing or running correctly. Common examples include:
Note that the Validator focuses on syntax only. It does not check whether tables or columns exist in your database, validate query logic, or assess performance. For query performance analysis, try the SQL Optimizer.
Yes. Your SQL queries are processed securely and are not stored. We collect only minimal, non-identifying data to improve the tool and monitor performance, including:
In rare cases, we may also log internal error messages for troubleshooting. These are unrelated to the syntax errors shown in the tool and never contain your original SQL code. We do not share any of this data with third parties.
Yes, the SQL Validator is completely free and requires no signup or account. You can use it as often as you'd like for personal or commercial work.
PostgreSQL has full support, meaning the Validator parses queries using PostgreSQL's own grammar across versions 7–18 and catches version-specific syntax issues. Basic support for other databases means the Validator uses a general SQL grammar to catch common syntax errors but may not recognize every dialect-specific feature, function, or keyword. If you're writing PostgreSQL, select your exact version for the most accurate results.
Select the version that matches your production or development database. PostgreSQL syntax evolves between major versions, and a query that's valid in PostgreSQL 16 may fail to parse in PostgreSQL 12.
A few examples of version-specific syntax:
If you're unsure which version you're on, run SELECT version(); in your database and pick the matching major version in the dropdown. Selecting the wrong version is one of the most common reasons a query shows as invalid when it actually runs fine elsewhere.
Yes - the Validator can check the syntax of stored procedures, user-defined functions, triggers, and anonymous procedural blocks. This is especially useful for PostgreSQL PL/pgSQL development, where you might be writing:
The Validator parses the procedural code as PostgreSQL itself would, catching mistakes in variable declarations, missing semicolons inside blocks, mismatched BEGIN/END pairs, and malformed control structures.
Keep in mind the Validator checks syntax only. It can't verify that referenced tables, columns, or functions exist, that data types align, or that the procedural logic produces the intended result. For those checks, test the function in a development database - for example, in the PostgreSQL Playground.
Yes. You can paste multiple statements separated by semicolons, and the Validator will check them as a batch. If one statement contains an error, the editor will highlight it so you can fix issues without re-checking the rest of your script.
A few common causes:
Wrong database or version selected. This is by far the most frequent reason. MySQL syntax checked against PostgreSQL (or vice versa) will surface errors that aren't real. Same for version mismatches - a MERGE statement is valid in PostgreSQL 15+ but invalid in 14 and earlier. Always confirm the database type and version in the dropdowns match your actual environment.
Vendor-specific extensions outside basic support. For databases marked "Basic support," the Validator uses a general SQL grammar that may not recognize every proprietary function, hint, or syntax extension. ClickHouse table engines, BigQuery's STRUCT syntax, or Snowflake's QUALIFY clause are examples of features that may not parse against basic-support dialects.
Session-specific or runtime context. Queries that reference temporary tables, session variables, prepared statements, or objects created by earlier statements in a script may parse fine in your live database but appear unresolved in an isolated check.
Server-side configuration. Some queries depend on settings like search_path, custom collations, or extensions installed in your database. The Validator doesn't know about your environment, so it parses against a default configuration.
Hidden characters from copy-paste. Occasionally, smart quotes, non-breaking spaces, or zero-width characters slip in when copying from documents or chat apps. These can cause the Validator to fail while your database silently tolerates them.
If your query is genuinely valid and you've ruled out the above, double-check that no recent syntax change in your dialect has outpaced the Validator's grammar - and feel free to send us feedback.
We're exploring an API version of the Validator for teams who want to integrate syntax checking into CI/CD pipelines, code editors, or internal tools. If you're interested, get in touch through our contact page.
Yes. Aiven offers official plugins for JetBrains IDEs (IntelliJ IDEA, DataGrip, PyCharm, and others) and a Visual Studio Code extension. Both integrate SQL validation, optimization, and formatting directly into your editor so you can catch issues without leaving your workflow.
Alongside the SQL Validator, Aiven offers a SQL Optimizer for query performance analysis, a SQL Formatter to beautify and standardize SQL code, and a PostgreSQL Playground for experimenting with PostgreSQL in your browser. All are free and require no signup.
Looking for more? Browse all of Aiven's free tools for developers.
