See what a SQL query does, step by step
Paste a query. It explains the steps in plain English, draws the joins and flags slow or risky patterns.
- Runs on your device
- No sign-up
- Works offline after a visit
—steps
—joins
—warnings
How to understand a SQL query
- Paste the SQL in the box. Statements separated by semicolons are read one by one.
- Read the steps in the order a database logically applies them, and the join picture below.
- Check the warnings, then copy the formatted SQL when it looks right.
Questions
Which SQL does it understand?
Common SQL: SELECT with joins, subqueries, CTEs, UNION, GROUP BY with ROLLUP, window functions, plus INSERT, UPDATE, DELETE and a basic CREATE TABLE. Syntax it does not know is reported with its line and column.
Does it run my query or connect to a database?
No. The query is read as text in your browser. Nothing is executed, and nothing is sent anywhere.
Why do the steps not follow the order I wrote?
They follow the logical order: FROM and JOIN first, then WHERE, GROUP BY, HAVING, SELECT, ORDER BY and LIMIT. A database may run the work differently, but the result is the same.
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