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题解 | #存在绩点大于该校平均绩点时的学生信息#

select u.device_id,u.university from user_profile u,( select university,avg(gpa) as avg_gpa from user_profile group by university havi...

2023-06-20

1 332

题解 | #为什么having后可以使用select定义的#

select university,count(device_id) as cnt,group_concat(device_id separator ';') as device_list from user_profile group by university having cnt<=2...

2023-06-20

0 441

题解 | #列出供应商及其可供产品的数量#

select v.vend_id,count(p.vend_id) prod_id from Vendors v left join Products p on v.vend_id=p.vend_id group by v.vend_id order by v.vend_id; 记录一下不难，但是错...

2023-06-06

0 301

题解 | #返回产品名称和与之相关的订单号#

select prod_name,order_num from Products p left join OrderItems o on p.prod_id=o.prod_id union select prod_name,order_num from Products p right join O...

2023-06-06

0 284

题解 | #96子查询顺序#

select prod_name, ( select sum(quantity) from OrderItems o where o.prod_id=p.prod_id ) as quant_sold from Products p; 子查询顺序是先内再外的话，为什么这里的括...

2023-06-06

2 635

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 OrderItems a,Orders b where a.order_num=b.order_num and a.item_price>=10;*/ /*select cust_id from OrderItems a left join Ord...

2023-06-06

1 381

题解 | #合并两个排序的链表#

/** * struct ListNode { * int val; * struct ListNode *next; * }; */ /** * * @param pHead1 ListNode类 * @param pHead2 ListNode类 * @return L...

2023-06-02

0 285

题解 | #反转链表#

/** * struct ListNode { * int val; * struct ListNode *next; * }; */ /** * * @param pHead ListNode类 * @return ListNode类 */ struct ListNode*...

2023-06-02

0 313