Is my query executed?

No. The analysis is purely static — the SQL is parsed with pattern rules in your browser and never sent anywhere.

Which dialects are supported?

The rules are dialect-agnostic and cover standard SQL used by PostgreSQL, MySQL, SQL Server, SQLite and others.

Can it replace EXPLAIN?

No. EXPLAIN uses real statistics from your database. This tool catches the structural mistakes before you get that far.

Are the index suggestions safe to run?

Treat them as a starting point. Check existing indexes, column cardinality and write throughput before creating any index.

Is my data uploaded to a server?

No. This tool runs entirely in your browser using standard web APIs, so your input never leaves your device and nothing is logged or stored on our servers.

SQL Query Analyzer

Find expensive SQL patterns, missing filters and index opportunities.

Support

Works Offline

Privacy First

No Login

No API

SQL query

Static analysis only — the query is never executed and never leaves your browser.

Analysis

Cost

46 · High

Joins

Subqueries

Issues

0E / 4W

Tables: orders, customers, order_items

warningSELECT * returns every column
Wildcard projections read and transfer columns the application may never use, and they break silently when the table changes.
→ List only the columns you need: SELECT id, name, created_at …
warningLeading-wildcard LIKE
A pattern that starts with % cannot use a B-tree index, so it forces a full scan.
→ Anchor the pattern (LIKE 'abc%'), or use a full-text / trigram index.
warningFunction applied to a filtered column
Wrapping a column in a function makes the predicate non-sargable, so the index on that column is ignored.
→ Rewrite the predicate (e.g. col >= '2026-01-01' AND col < '2026-02-01') or add a functional/expression index.
infoORDER BY without LIMIT
Sorting the full result set costs memory and may spill to disk.
→ Add LIMIT/OFFSET, or sort in the application when the set is small.
warningLarge OFFSET pagination
OFFSET N still reads and discards N rows on every page.
→ Use keyset pagination: WHERE id > :last_id ORDER BY id LIMIT :n.

Suggested indexes

CREATE INDEX idx_o_status ON o (status);
CREATE INDEX idx_c_id ON c (id);
CREATE INDEX idx_o_customer_id ON o (customer_id);
CREATE INDEX idx_i_order_id ON i (order_id);
CREATE INDEX idx_o_id ON o (id);

Hints are derived from WHERE, ON and ORDER BY columns — verify against your real cardinality and existing indexes.

About the SQL Query Analyzer

Paste a SQL statement to get a static review: SELECT *, missing WHERE clauses, UPDATE/DELETE without filters, leading-wildcard LIKE, non-sargable functions on filtered columns, NOT IN subqueries, implicit cross joins, joins without ON, deep OFFSET pagination, UNION versus UNION ALL and more — plus a cost estimate and ready-to-run CREATE INDEX suggestions.

Examples

Wildcard select

SQLSELECT * FROM orders

Output

YAMLWarning: SELECT * and no WHERE clause

Keyboard shortcuts

Copy the main outputCtrl / ⌘ + Shift + C
Download the resultCtrl / ⌘ + S
Share this toolCtrl / ⌘ + Shift + S
Reset the inputsAlt + R
Open the tool search paletteCtrl / ⌘ + K

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Version 1.0.0 · Updated 2026-08-17 · Runs entirely in your browser

SQL Query Analyzer

Suggested indexes

About the SQL Query Analyzer

Examples

Keyboard shortcuts

Related tools

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Frequently asked questions

Is my query executed?

Which dialects are supported?

Can it replace EXPLAIN?

Are the index suggestions safe to run?

Is my data uploaded to a server?

Read more

Suggested indexes