SQL JOIN Fan-Out Visualizer

Build your own orders and watch a one-to-many JOIN quietly multiply your revenue before you ever call SUM()

Editable Orders Real SQLite Engine Free, No Signup

Your orders

Each chip below is one row your query sees after joining to line items — the same order total, repeated once per item.

Total after the JOIN (buggy)

$0.00

Actual revenue (correct)

$0.00

+0%

Inflation

Buggy — sums after the JOIN

Correct — sums before joining

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This runs on a real, self-hosted SQLite engine (WebAssembly) — nothing is sent to a server. Read the full mechanism in Why Does My SQL Query Return the Correct Rows but the Wrong Numbers? and Why Is My SQL SUM() Wrong After a JOIN?