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made changes in joins

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Dmitry Medvedev
2026-06-04 15:05:34 +05:00
parent fe31e93ad3
commit d989ceedf3
1 changed files with 17 additions and 17 deletions
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dmedvedev/joins. sql → dmedvedev/joins.sql
+17 -17
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@@ -79,7 +79,7 @@ SELECT
o.id AS order_id,
o.status AS status
FROM users u
FULL JOIN orders o ON o.user_id = u.id;
LEFT JOIN orders o ON o.user_id = u.id;
/*
**✅ После выполнения:**
@@ -97,8 +97,8 @@ FULL JOIN orders o ON o.user_id = u.id;
SELECT
o.user_id AS user_id,
u.name AS user_name
FROM orders o
FULL JOIN users u ON o.user_id = u.id
FROM users u
LEFT JOIN orders o ON o.user_id = u.id
WHERE user_id IS NULL;
/* **❓ Ответь на вопросы:**
@@ -119,9 +119,9 @@ SELECT
p.name AS product_name,
oi.quantity AS quantity
FROM order_items oi
FULL JOIN orders o ON o.id = oi.order_id
FULL JOIN users u ON o.user_id = u.id
FULL JOIN products p ON p.id = oi.product_id
JOIN orders o ON o.id = oi.order_id
JOIN users u ON o.user_id = u.id
JOIN products p ON p.id = oi.product_id
WHERE p.name = 'Kindle';
/*Ответь на вопросы:**
@@ -138,9 +138,9 @@ SELECT
p.name AS product_name,
oi.order_id AS order_id,
oi.quantity AS quantity
FROM order_items oi
FULL JOIN orders o ON o.id = oi.order_id
FULL JOIN products p ON p.id = oi.product_id
FROM products p
FULL JOIN order_items oi ON p.id = oi.product_id
ORDER BY p.name
/*❓ Ответь на вопросы:
что будет в order_id, если товар ни разу не покупали?
@@ -179,9 +179,9 @@ SELECT
oi.quantity AS quantity,
oi.price_at_purchase AS price_at_purchase
FROM order_items oi
FULL JOIN orders o ON o.id = oi.order_id
FULL JOIN products p ON p.id = oi.product_id
FULL JOIN users u ON u.id = o.user_id
JOIN orders o ON o.id = oi.order_id
JOIN products p ON p.id = oi.product_id
JOIN users u ON u.id = o.user_id
WHERE u.name = 'Alice';
/**❓ Ответь на вопросы:**
@@ -195,11 +195,11 @@ SELECT
oi.order_id AS order_id,
o.user_id AS user_id,
o.status AS status,
u.name AS name
FROM order_items oi
FULL JOIN orders o ON o.id = oi.order_id
FULL JOIN products p ON p.id = oi.product_id
FULL JOIN users u ON u.id = o.user_id;
oi.product_id AS product
FROM orders o
LEFT JOIN order_items oi ON o.id = oi.order_id
LEFT JOIN products p ON p.id = oi.product_id
WHERE oi.product_id IS NULL;
/*
**❓ Ответь на вопросы:**