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643 B
643 B
title, layout, updated, weight
| title | layout | updated | weight |
|---|---|---|---|
| SQL joins | 2017/sheet | 2017-10-30 | -1 |
Example
SELECT * FROM order_items LEFT OUTER JOIN orders ON order_items.order_id = orders.id
{: .-wrap}
Diagram
┌────────┐
│ A ┌───┼────┐
│ │ ∩ │ │
└────┼───┘ B │
└────────┘
{: .-box-chars}
| Join | What |
|---|---|
| Inner join | ∩ |
| Left outer join | A + ∩ |
| Right outer join | ∩ + B |
| Full outer join | A + ∩ + B |