SQL Syntax Checker & Validator

What is a SQL Syntax Validator?

A SQL syntax validator checks a query for errors before you run it against a database, saving you a round-trip to the server and the pain of deciphering cryptic parser errors. Paste your SQL, pick a dialect, and the tool flags problems on the exact line where they occur — missing commas, misspelled keywords like SELCET, unmatched parentheses, and malformed structure. It combines a real SQL parser (supporting 15+ dialects including MySQL, PostgreSQL, SQLite, BigQuery, Snowflake, and T-SQL) with heuristic checks that catch common typos the parser might otherwise overlook. Everything runs in your browser, so sensitive production queries are never sent to a server. The value is speed and confidence: you get immediate feedback on the exact line of the mistake instead of waiting for a database error after deployment. It is also a handy learning aid, since seeing the precise location of a mistake is far more instructive than a vague “syntax error” message.

How to Use the Validator

1. Paste your SQL into the editor — line numbers appear automatically on the left.
2. Select your database dialect from the dropdown (Standard SQL, MySQL, PostgreSQL, and more).
3. Click Validate, or press Ctrl+Enter.
4. Read the results panel: errors are marked red, warnings orange, and a green summary appears when the query is clean.
5. Fix the flagged lines, then re-run. Use the example buttons (missing comma, wrong keyword, unmatched paren) to see the validator in action.

Common Use Cases

• Catching typos in hand-written queries before they hit a production database.
• Validating SQL generated by ORMs, BI tools, or copied from documentation.
• Checking dialect-specific syntax when porting a query between databases.
• Teaching SQL by showing learners exactly where their query broke.
• Sanity-checking migration scripts and stored procedures before deployment.
• Reviewing queries in code review where a quick syntax gate prevents obvious mistakes from merging.

Example

Paste a query with a typo and a missing comma, and the validator reports both problems on their exact lines.

Tips

Run the validator before formatting or minifying — a query with broken syntax will produce misleading output in other tools. Always choose the right dialect: syntax that is valid in PostgreSQL (such as RETURNING or :: casts) may not be valid in MySQL, and vice versa. The validator reports the first structural error from the parser plus independent typo and bracket warnings, so fix errors top-down and re-run after each change. Remember that a “clean” result means the syntax is valid, not that the query returns correct results — still review the logic and test against real data before shipping. For the clearest results, validate one statement at a time — isolating a query produces more accurate line numbers than dumping an entire script in one go. And since every check runs locally in your browser, you can validate even the most sensitive production queries without a second thought.

SQL Syntax Checker: Check SQL Online in One Click

A syntax checker answers one question fast: will this SQL parse? Paste the query into the editor above, pick the dialect, and the checker runs a real parser over the text and reports the first structural error plus independent typo and bracket warnings, each anchored to the exact line where it occurs. That is most valuable for SQL you did not write yourself — output from an ORM, a statement generated by a BI tool, a snippet copied from documentation, or a migration script that has to be right the first time. Unlike a style linter, this checker fails loudly on the things that actually break a query: a missing comma between two columns, a misspelled keyword such as SELCET, an unbalanced parenthesis, or a clause in the wrong order. Everything runs in your browser with no upload, so you can check production queries and internal schemas without a privacy review. If you are debugging a “syntax error near …” message from MySQL, PostgreSQL or SQL Server, run the SQL syntax checker first — it usually surfaces the real problem in a second instead of another round trip to the database. Once the query is clean, format it with the free SQL formatter and read the plan behind it in the SQL EXPLAIN visualizer.

MySQL, PostgreSQL, Oracle and SQL Server Validators

Every dialect has its own grammar, and a query that parses in one engine can fail in the next. The validator ships with 15+ grammars, so you validate against the database you actually deploy to rather than Standard SQL. These are the dialect differences that trip people up most often:

• PostgreSQL validator — accepts RETURNING, :: casts, ON CONFLICT, DISTINCT ON, LATERAL joins, dollar-quoted strings and JSONB operators (->, ->>, @>). All of these are rejected by MySQL. Pair it with the PostgreSQL formatter when you are done.
• MySQL / MariaDB validator — accepts backtick-quoted identifiers, LIMIT offset, count and INSERT ... ON DUPLICATE KEY UPDATE. MySQL error 1064 is nearly always a missing comma or a dialect mismatch, and checking MySQL syntax here catches both before you touch production. See the MySQL formatter for the formatting side.
• SQL Server (T-SQL) validator — for SELECT TOP n, [bracketed] identifiers, GO batch separators and MERGE statements.
• Oracle (PL/SQL) validator — handles DUAL, ROWNUM, NVL, CONNECT BY and PL/SQL blocks that are not wrapped in a stored procedure.
• SQLite, BigQuery, Snowflake, Redshift, Spark, Hive, DB2, Trino — pick the matching grammar for warehouse and embedded-database SQL.

Choosing the wrong dialect is the most common cause of false alarms: a query flagged under Standard SQL often parses cleanly the moment you switch to the engine you are targeting. Validate with the same engine you will run against. When you need to move a query between engines, check the differences first with the SQL dialect converter.

How to Fix a SQL Query Error (Fix My SQL Query)

When a query fails, the database message points at where the parser gave up — not always where you went wrong. The real mistake is often a few lines earlier. Work top-down:

1. Read the reported line, then scan the two or three lines above it.
2. Check the commas: a missing comma between two selected columns or two join conditions is the single most common defect.
3. Check keyword spelling — SELCET, FORM, WHEER, GRUOP BY.
4. Check clause order: SELECT ... FROM ... JOIN ... WHERE ... GROUP BY ... HAVING ... ORDER BY ... LIMIT.
5. Balance parentheses and quotes, and look for a trailing comma before FROM.
6. Confirm the dialect, then re-validate.

Re-run the validator after each fix. It reports the first structural error per run, so a brand new message usually means you have moved on to the next problem. Once the query validates, compare the original with the repaired version using the SQL diff tool — seeing both side by side is the quickest way to confirm the logic still matches your intent. Keep one thing in mind: a clean result proves the SQL parses, not that it returns the rows you expect. Always test against real data before shipping.

Frequently Asked Questions

What SQL errors can the validator detect?

It detects syntax errors such as missing commas, unmatched parentheses, misspelled keywords (for example SELCET instead of SELECT) and structural problems that would make the query fail. Errors are reported line by line, with warnings flagged separately from hard errors.

Does validation require sending my query to a server?

No. All validation runs client-side in your browser. Your SQL never leaves your device — nothing is uploaded, so you can check production queries and proprietary schemas safely.

Which SQL dialects can I validate?

15+ dialects, including MySQL, PostgreSQL, SQLite, BigQuery, DB2, Hive, MariaDB, PL/SQL, Redshift, SingleStoreDB, Snowflake, Spark SQL, T-SQL and Trino. Pick your dialect from the dropdown before validating.

What is the difference between a SQL syntax checker and a SQL validator?

In practice they do the same job. A checker confirms that your statement parses under a given grammar; a validator does the same and adds typo and bracket heuristics. This tool does both in one pass, which is why the terms SQL syntax checker, SQL validator, SQL query checker and SQL linter all point at the tool above.

Can I validate a PostgreSQL or MySQL query online?

Yes. Select PostgreSQL, MySQL or MariaDB from the dialect dropdown. Syntax that is valid in PostgreSQL (RETURNING, :: casts, DISTINCT ON) is flagged under MySQL, and MySQL's backtick identifiers and LIMIT offset, count form are not standard SQL. Choosing the right dialect removes most false errors.

How do I fix a SQL query that will not run?

Start at the reported line and scan upward. Most failures come from a missing comma, a misspelled keyword, unbalanced parentheses or clauses out of order. Fix one issue and re-validate — each run reports the first structural error. Then compare the repaired query with the original using the SQL diff tool.

Is the SQL validator free and private?

Yes. It is free with no signup, and every check runs locally in your browser, so your SQL is never sent to a server.