Koľko riadkov vráti LEFT JOIN?
číslo15 b.
Dve tabuľky:
customers
| id | name |
|---|---|
| 1 | Anna |
| 2 | Boris |
| 3 | Cyril |
| 4 | Dana |
orders
| id | customer_id | total |
|---|---|---|
| 10 | 1 | 240 |
| 11 | 1 | 250 |
| 12 | 2 | 120 |
| 13 | 2 | 60 |
| 14 | 2 | 900 |
Koľko riadkov vráti tento dotaz?
SELECT c.name, o.id, o.total
FROM customers AS c
LEFT JOIN orders AS o ON o.customer_id = c.id;