SQL Linter

Paste a query to catch anti-patterns, ambiguous references, and style issues — entirely in your browser. Nothing you paste is sent anywhere.

How to use:

  1. Paste your SQL query into the editor on the left
  2. Select the dialect your query targets (PostgreSQL, MySQL, BigQuery, Snowflake, …)
  3. Diagnostics appear automatically as you type — no button needed
  4. Click any diagnostic to jump to the offending line and column
  5. Fix the flagged issues until the diagnostics pane reports no issues
Query
Diagnostics

Results will appear here as you type.

About this tool

SQL Linter is a free online tool that reviews your SQL for anti-patterns and style problems — SELECT *, comma-style implicit joins, missing WHERE clauses, ambiguous references, and more. Every query is analyzed locally in your browser; nothing is uploaded.

Dialects
Standard SQL (ANSI), PostgreSQL, MySQL, SQLite, BigQuery, Snowflake, SQL Server (T-SQL)
Output
Diagnostics with severity, rule code, explanation, and line:column position
Input
Pasted SQL text
Signup
Not required
Processing
Entirely in your browser — pasted SQL is never uploaded for analysis
Price
Free, no usage limits

Limitations

  • A style linter is a helpful reviewer, not a substitute for testing your queries
  • Very large scripts (thousands of statements) take longer to analyze

SQL Linter — FAQ

Is the SQL Linter free?

Yes. The SQL Linter is completely free with no signup and no usage limits, like all SqlInt mini tools.

What issues does the linter catch?

Anti-patterns like SELECT *, implicit comma joins, missing WHERE clauses, and ambiguous references — with line-by-line diagnostics.

Does linting change my query?

No. The linter only reports diagnostics; it never rewrites SQL — use the SQL Formatter to reformat.

Does my data leave my browser?

No. Every mini tool processes data locally in your browser — pasted text and uploaded files never leave your device.

SQL Formatter

Beautify SQL live with instant preview across 7 dialects.

CSV to SQL

Turn CSV into CREATE TABLE + INSERTs with auto-detected types.

JSON ↔ SQL

Convert JSON arrays to SQL — and INSERTs back to JSON — live.

JOIN Visualizer

Visualize INNER, LEFT, RIGHT, FULL & CROSS joins across up to 3 chained tables.