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题解 | #返回每个顾客不同订单的总金额#

SELECT a.cust_id, SUM(b.item_price*b.quantity) total_ordered FROM Orders a, OrderItems b WHERE a.order_num = b.order_num GROUP BY a.cust_id ORDER BY ...

2023-10-02

0 298

题解 | #返回购买 prod_id 为 BR01 的产品#

SELECT c.cust_email FROM Customers c LEFT JOIN Orders o ON c.cust_id = o.cust_id LEFT JOIN OrderItems a ON o.order_num = a.order_num WHERE a.prod_id =...

2023-10-02

0 434

题解 | #确定哪些订单购买了 prod_id BR01#

SELECT cust_id, order_date FROM Orders WHERE order_num IN ( SELECT order_num FROM OrderItems WHERE prod_id = 'BR01' ) ORDER BY order_date...

2023-10-02

0 237

题解 | #返回购买价格为 10 美元或以上产品的顾客列表#

SELECT cust_id FROM Orders WHERE order_num IN ( SELECT order_num FROM OrderItems WHERE item_price>=10 ) 子查询题解：1.任务：找到顾客列表2.限制：10美元及以上思路...

2023-10-02

0 242

题解 | #纠错3#

SELECT order_num, COUNT(*) AS items FROM OrderItems GROUP BY order_num HAVING items >= 3 ORDER BY items, order_num; 1.group by中必须包含select语句中的非聚...

2023-10-02

0 309

题解 | #计算总和#

SELECT order_num, SUM(item_price * quantity) total_price FROM OrderItems GROUP BY order_num HAVING total_price >= 1000 ORDER BY order_num 题解：1.任务：...

2023-10-02

0 209

题解 | #返回订单数量总和不小于100的所有订单的订单号#

SELECT order_num FROM ( SELECT order_num, SUM(quantity) FROM OrderItems GROUP BY order_num HAVING SUM(quantity) >= 100 ) a ORDER BY...

2023-10-02

0 268

题解 | #每个供应商成本最低的产品#

SELECT vend_id, MIN(prod_price) cheapest_item FROM Products GROUP BY vend_id ORDER BY cheapest_item 题解：1.任务：查询每个供应商成本最低的产品2.排序思路：1.使用min函数求最低成本2.使用gro...

2023-10-02

0 215

题解 | #返回每个订单号各有多少行数#

SELECT order_num, COUNT(*) order_lines FROM OrderItems GROUP BY order_num ORDER BY order_lines 题解：1.查询行数，就是记录数2.查询每个订单号的，也就是分组3.按订单记录数升序排序思路：1.查询记录数，使...

2023-10-02

0 400

题解 | #确定 Products 表中价格不超过 10 #

SELECT MAX(prod_price) max_price FROM Products WHERE prod_price <= 10 易错：不超过 = 小于等于题解：1.任务：求最贵产品的价格2.限制：不超过10美元思路：1.使用max函数求最大值2.where语句限制条件

2023-10-02

0 271