力扣sql中等篇练习(二十五)

1 最繁忙的机场

1.1 题目内容

1.1.1 基本题目信息

1.1.2 示例输入输出

a 示例输入

b 示例输出

1.2 示例sql语句

# Write your MySQL query statement below
WITH T as
(
    SELECT t.airport_id,SUM(n) num
    FROM
    (
       SELECT departure_airport airport_id,flights_count n
       FROM Flights 
       UNION ALL
       SELECT arrival_airport airport_id,flights_count n
       FROM Flights 
    )t
    GROUP BY t.airport_id
)
SELECT airport_id
FROM T
WHERE num=
(
    SELECT MAX(num)
    FROM T
)

1.3 运行截图

2 每辆车的乘客人数I

2.1 题目内容

2.1.1 基本题目信息1

2.1.2 基本题目信息2

2.1.3 示例输入输出

a 示例输入

b 示例输出

2.2 示例sql语句

# 满足乘车条件的车辆很多,需要选最早达到时间的那辆
# 然后与公交达到时间表右外连接即可
# 计算连接后的个数,应该count(另外一个表的非连接字段)
SELECT b1.bus_id,IFNULL(count(t.passenger_id),0) passengers_cnt
FROM
(
    SELECT p.passenger_id,MIN(b.arrival_time) min_arrival_time
    FROM Buses b
    LEFT JOIN Passengers p
    ON p.arrival_time<=b.arrival_time
    GROUP BY p.passenger_id
)t
RIGHT JOIN Buses b1
ON b1.arrival_time=t.min_arrival_time
GROUP BY b1.bus_id
ORDER BY b1.bus_id asc

2.3 运行截图

3 分别排序两列

3.1 题目内容

3.1.1 基本题目信息

3.1.2 示例输入输出

3.2 示例sql语句

#  ROW_NUMBER() OVER(ORDER BY 列名 升序或者降序) 给出对应序列的排名
SELECT t1.first_col,t2.second_col
FROM
(
    SELECT first_col,ROW_NUMBER() over(ORDER BY first_col asc) r
    FROM Data
) t1
INNER JOIN
(
    SELECT second_col,ROW_NUMBER() OVER(ORDER BY second_col desc) r
    FROM Data
) t2
ON t1.r=t2.r

3.3 运行截图