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SQL Checker

Paste SQL and run a quick client-side check for common syntax pitfalls and risky patterns. This is a lightweight validator (not a full DB parser), so it focuses on fast, practical checks.

Category: Data · URL: /tools/sql-checker.html
Client-side only. This tool catches common issues (quotes/comments/parentheses, risky patterns) but does not fully parse every dialect feature.

    

  


  

    
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            Privacy: runs locally in your browser. No uploads, no tracking scripts.
          

        

      


      
    


    

      
How to use

      
Use it as a fast pre-check before running queries in a database console.
  1. Paste your SQL into the input box.
  2. Select a dialect (affects quoting rules and a few heuristics).
  3. Click Check SQL to get a compact report (errors + warnings).
  4. Optional: click Format to improve readability, then re-check.

      

        Keywords this page targets (natural cluster): sql checker, sql syntax checker, check sql query, sql query validator, sql lint online, validate sql statement, sql parentheses checker, sql quote checker, unclosed string literal sql, unclosed comment sql, detect multiple sql statements, update without where check, delete without where check, sql formatting and validation, mysql sql checker, postgres sql checker, sql server query checker, sqlite sql checker, sql injection risky query check, sql semicolon checker, sql statement splitter
      

      

        Secondary intents covered: Find unclosed string literals, identifiers, or comments in SQL, Detect mismatched parentheses and basic structural issues, Warn on UPDATE/DELETE statements missing a WHERE clause, Check if multiple statements are present (and optionally disallow them), Quickly format SQL for readability before sharing/debugging, Generate a compact report you can copy into tickets or reviews, Spot common INSERT column/value count mismatches (simple cases), Standardize keyword casing for easier review
      

    


    

      
FAQ

    
Is this a full SQL parser for my database?
No—it's a lightweight checker that focuses on common, high-signal issues (quotes/comments/parentheses, multiple statements, risky UPDATE/DELETE patterns).
Does it run server-side or send my SQL anywhere?
No. It runs entirely in your browser and does not make network requests.
Why do I see a warning for UPDATE/DELETE without WHERE?
Because it often indicates an accidental full-table change. Some workflows are intentional—treat it as a safety prompt.
Can it detect SQL injection?
Not reliably. It can flag risky patterns (like multiple statements), but injection prevention depends on parameterized queries in your app.
Why does SELECT without FROM show a warning?
Some databases allow it (for expressions), but many queries expect a FROM clause—so it’s flagged as a gentle review hint.
Will the formatter change query meaning?
It only adjusts whitespace/casing and adds line breaks outside of quotes/comments, but you should still re-check before running in production.
How does it handle different dialects (MySQL/Postgres/SQL Server)?
Dialect mainly tweaks quoting/comment rules (e.g., MySQL backslash escapes, SQL Server bracket identifiers). The checks are otherwise generic.