How to Validate SQL Queries Online: Step-by-Step Tutorial

Step 1: Open the SQL Validator

Go to the SQL Validator page. You will see a code editor area, a dialect selector, and mode tabs for Validate, Format, and Explain. The validator is selected by default.

Step 2: Select Your Dialect

Use the dialect dropdown to select your target database: Generic SQL, PostgreSQL, MySQL, T-SQL (SQL Server), or SQLite. This is important because each dialect has different syntax rules. A query that is valid in PostgreSQL may be invalid in MySQL.

If you are unsure, start with Generic SQL. You can switch dialects and re-validate to see dialect-specific issues.

Step 3: Paste Your SQL

Paste your SQL query into the editor. The editor supports tab indentation and Ctrl+Enter to run the validator. You can also click the "Load Sample" button to try a sample query.

Example Query to Validate

SELECT c.name, COUNT(o.id
FROM customers c
JOIN orders o ON c.id = o.customer_id
WHERE o.status = 'paid'
GROUP BY c.name

This query has a deliberate error — an unclosed parenthesis after COUNT(o.id.

Step 4: Click "Validate SQL"

Click the blue "Validate SQL" button or press Ctrl+Enter. The results panel appears below the editor with a summary badge and a detailed list of errors and warnings.

Step 5: Review the Results

The validator shows:

• Error badge — Red for errors, yellow for warnings only, green for valid
• Error list — Each error with a description and line number when available
• Statistics — Statement count, query type, whether DDL is present, and the active dialect

Fix the reported errors in your SQL and validate again until the result shows green.

Step 6: Try Dialect-Specific Validation

Change the dialect to see different results. For example, this query is valid in PostgreSQL but invalid in MySQL:

SELECT name::text FROM users WHERE name ILIKE '%john%'

With PostgreSQL selected, it passes. Switch to MySQL and you get two errors: :: is not supported and ILIKE is not available.

Step 7: Check for Dangerous Queries

The validator warns about dangerous operations. Try pasting:

DELETE FROM orders

The validator flags this with a warning: "DELETE without WHERE clause — this will delete ALL rows." This is syntactically valid SQL, but almost certainly not what you intended.

Step 8: Share Your Validation

Click the Share button to generate a URL that anyone can open to see the same SQL and validation results. The SQL is encoded in the URL — no server storage is involved.

Next Steps

After validating your SQL, use the SQL Formatter to clean up the formatting, and the SQL Query Explainer to get a plain English breakdown of what the query does.