JoKerhhh

分类

/ 注册

全部文章（共34篇）

题解 | #修改表#

ALTER TABLE user_info add column school varchar(15) after level, #在level后新增列 change column job profession varchar(10), #把job改为profession modify column...

2024-01-22

0 141

题解 | #创建一张新表#

CREATE TABLE IF NOT EXISTS user_info_vip( id int primary key auto_increment comment '自增ID', uid int unique NOT NULL comment '用户ID', nick_n...

2024-01-22

0 137

题解 | #删除记录（二）#

delete from exam_record WHERE timestampdiff(MINUTE,start_time,submit_time) < 5 OR submit_time is NULL ORDER BY start_time LIMIT 3; 时间差：TIMESTAMPDI...

2024-01-22

0 146

题解 | #列出供应商及其可供产品的数量#

SELECT vd.vend_id, COALESCE(COUNT(prod_id),0) AS prod_id FROM Vendors AS vd LEFT JOIN Products AS p ON vd.vend_id = p.vend_id GROUP BY vend_id ORDER ...

2024-01-21

0 126

题解 | #确定最佳顾客的另一种方式（二）#

select ct.cust_name, SUM(ot.item_price * ot.quantity) AS total_price FROM OrderItems AS ot JOIN Orders AS od ON od.order_num = ot.order_num JOIN Custo...

2024-01-21

0 278

题解 prod_id 为 BR01 的产品顾客的电子邮件

select ct.cust_email FROM Customers AS ct JOIN Orders AS od ON od.cust_id = ct.cust_id JOIN OrderItems AS ot ON ot.order_num = od.order_num AND ot.pro...

2024-01-21

0 190

题解 | # prod_id 为 BR01 的产品

select cust_id, order_date FROM OrderItems AS ot JOIN Orders AS od ON ot.order_num = od.order_num AND ot.prod_id = 'BR01' ORDER BY order_date

2024-01-21

0 176

题解 | #返回顾客名称和相关订单号以及每个订单的总价#

select ct.cust_name, od.order_num, ot.quantity * ot.item_price AS OrderTotal FROM Customers AS ct JOIN Orders AS od ON ct.cust_id = od.cust_id JOIN O...

2024-01-21

0 124

题解 | #返回顾客名称和相关订单号#

select cust_name, ( select order_num FROM Orders AS b WHERE b.cust_id = a.cust_id ) order_num FROM Customers AS a ORDER BY cust_name,order_n...

2024-01-21

0 172

题解 | Products 表中检索所有的产品名称及数量

select prod_name, ( select SUM(quantity) FROM OrderItems AS a WHERE a.prod_id = b.prod_id ) AS quant_sold FROM Products AS b 描述 Products ...

2024-01-21

0 550