AI Tool · Optimize

Optimize a slow SQL query

Paste a query that’s dragging and get specific, actionable suggestions — indexes to add, sargable rewrites, joins that beat correlated subqueries — each with a short reason so you learn why it’s faster, not just what to change.

1Paste your SQL into the formatter.

2Click Optimize.

3Apply the suggested indexes and rewrites.

Optimize a query

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before — slow

SELECT *
FROM orders o
WHERE YEAR(o.created_at) = 2026
  AND o.customer_id IN (SELECT id FROM customers WHERE country = 'US')
ORDER BY o.total DESC;

Suggested optimizations

Avoid wrapping the column in a function

YEAR(o.created_at) = 2026 can't use an index on created_at. Rewrite as a range: created_at >= '2026-01-01' AND created_at < '2027-01-01'.

Turn the IN-subquery into a JOIN

A JOIN to customers on a filtered country lets the planner use an index and estimate rows better than a correlated IN.

Select only the columns you need

SELECT * forces the engine to read and return every column; list the ones the caller actually uses.

Add a supporting index

An index on orders(created_at, total) helps both the range filter and the ORDER BY.

Why optimize SQL with AI?

Most slow queries share a handful of causes: a function wrapped around an indexed column, SELECT * pulling columns nobody reads, a correlated subquery the planner can’t flatten, or a missing composite index. Spotting them in someone else’s query takes experience — the optimizer names the specific issue in your SQL and gives you the rewrite.

It’s a starting point, not a replacement for EXPLAIN: use the suggestions to form a hypothesis, then confirm the win against your real data and query plan.

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