INNER JOIN
Returns only rows where join keys exist in both inputs.
Kept rows: matched rows only (intersection).
Use when you only want confirmed relationships.
Server-Aware JOIN Playground
JOIN Function Visualizer
Choose your server type, pick a JOIN function, and visualize how two query results merge. This page runs fully static in the browser.
For local testing, open this page through a local static server so script and style files load from your workspace.
JOIN Visualizer Input
Server compatibility note will appear here.
JOIN Merge Visualization
Run Visualize JOIN to see the merge flow between both input queries.
Run Visualize JOIN to see sample merged rows.
Detailed JOIN Explanations
Each JOIN type below explains what rows are kept and when to use it.
Tip: click a JOIN card in Detailed JOIN Explanations to preview kept rows. Muted rows are not deleted; click Visualize JOIN to regenerate the actual row set.
LEFT JOIN
Keeps every row from left input and matches right when possible.
Kept rows: all left rows plus matched right rows.
Use when left input is primary and right is optional.
RIGHT JOIN
Keeps every row from right input and matches left when possible.
Kept rows: all right rows plus matched left rows.
Use when right input is primary and left is optional.
FULL JOIN
Keeps all rows from both sides; unmatched columns become NULL.
Kept rows: left-only, matched, and right-only rows.
Use for reconciliation and mismatch discovery.
CROSS JOIN
Returns all combinations between left and right rows.
Kept rows: cartesian product (every left row with every right row).
Use for matrix expansion and combinations.
Choose a JOIN type to see a deeper operational explanation.