完了済

Answers/Question2alpha.txt

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+--Q1
+SELECT items.item_id AS '商品ID',
+       items.name AS '商品名',
+       items.price AS '価格',
+       item_category.name AS 'カテゴリ名'
+FROM items INNER JOIN item_category ON items.category_id = item_category.category_id
+ORDER BY items.item_id ASC;
+
+--Q2
+SELECT orders.order_id AS '注文ID',
+       orders.order_time AS '注文日時',
+       users.name AS 'ユーザ名',
+       items.name AS '商品名',
+       items.price AS '価格',
+       order_items.quantity AS '数量'
+FROM orders
+    INNER JOIN order_items ON orders.order_id = order_items.order_id
+    INNER JOIN users ON orders.user_id = users.user_id
+    INNER JOIN items ON order_items.item_id = items.item_id
+ORDER BY orders.order_id ASC;
+
+--Q3
+SELECT orders.order_id AS '注文ID',
+       orders.order_time AS '注文日時',
+       users.name AS 'ユーザ名',
+       SUM(items.price*order_items.quantity) AS '合計額'
+FROM orders
+    INNER JOIN order_items ON orders.order_id = order_items.order_id
+    INNER JOIN users ON orders.user_id = users.user_id
+    INNER JOIN items ON order_items.item_id = items.item_id
+GROUP BY orders.order_id
+ORDER BY orders.order_id ASC;
+
+--Q4
+SELECT SUBSTRING(orders.order_time, 1, 7) AS '注文月',
+       SUM(order_items.quantity) AS '注文数'
+FROM orders
+    INNER JOIN order_items ON orders.order_id = order_items.order_id
+GROUP BY SUBSTRING(orders.order_time, 1, 7);
+
+--Q5
+SELECT SUBSTRING(orders.order_time, 1, 4) AS '注文年',
+       SUM(order_items.quantity*items.price) AS '売上額'
+FROM orders
+    INNER JOIN order_items ON orders.order_id = order_items.order_id
+    INNER JOIN items ON order_items.item_id = items.item_id
+GROUP BY SUBSTRING(orders.order_time, 1, 4)
+ORDER BY SUBSTRING(orders.order_time, 1, 4) ASC;
+
+--Q6
+SELECT SUM(order_items.quantity*items.price) AS '売上額'
+FROM order_items INNER JOIN items ON order_items.item_id = items.item_id;
+
+--Q7
+SELECT item_category.name AS 'カテゴリ名', 
+       SUM(order_items.quantity*items.price) AS '売上額'
+FROM order_items
+    INNER JOIN items ON items.item_id = order_items.item_id
+    INNER JOIN item_category ON item_category.category_id = items.category_id
+GROUP BY item_category.category_id
+ORDER BY 売上額 DESC;
+
+--Q8
+SELECT items.name AS '商品名', 
+       SUM(order_items.quantity*items.price) AS '売上額'
+FROM order_items
+    INNER JOIN items ON items.item_id = order_items.item_id
+GROUP BY items.name
+ORDER BY 売上額 DESC;
+
+--Q9
+SELECT item_category.name AS 'カテゴリ名', 
+       SUM( 100*order_items.quantity*items.price/ 
+            (SELECT SUM(order_items.quantity*items.price)
+             FROM order_items INNER JOIN items ON order_items.item_id = items.item_id) ) AS '構成比（％）'
+FROM order_items
+    INNER JOIN items ON items.item_id = order_items.item_id
+    INNER JOIN item_category ON item_category.category_id = items.category_id
+GROUP BY item_category.category_id
+ORDER BY 構成比（％） DESC;
+
+--Q10
+SELECT items.name AS '商品名', 
+       SUM( 100*order_items.quantity*items.price/ 
+            (SELECT SUM(order_items.quantity*items.price)
+             FROM order_items INNER JOIN items ON order_items.item_id = items.item_id) ) AS '構成比（％）'
+FROM order_items
+    INNER JOIN items ON items.item_id = order_items.item_id
+GROUP BY items.name
+ORDER BY 構成比（％） DESC;