Skip to content

Files

Latest commit

c5dbbb6 · Jun 16, 2023

History

History
116 lines (97 loc) · 2.87 KB

File metadata and controls

116 lines (97 loc) · 2.87 KB

English Version

题目描述

表:Sessions

+---------------------+---------+
| Column Name         | Type    |
+---------------------+---------+
| session_id          | int     |
| duration            | int     |
+---------------------+---------+
session_id 是该表主键
duration 是用户访问应用的时间, 以秒为单位

 

你想知道用户在你的 app 上的访问时长情况。因此决定统计访问时长区间分别为 "[0-5>", "[5-10>", "[10-15>" 和 "15 or more" (单位:分钟)的会话数量,并以此绘制柱状图。

写一个SQL查询来报告(访问时长区间,会话总数)。结果可用任何顺序呈现。

 

下方为查询的输出格式:

Sessions 表:
+-------------+---------------+
| session_id  | duration      |
+-------------+---------------+
| 1           | 30            |
| 2           | 199           |
| 3           | 299           |
| 4           | 580           |
| 5           | 1000          |
+-------------+---------------+

Result 表:
+--------------+--------------+
| bin          | total        |
+--------------+--------------+
| [0-5>        | 3            |
| [5-10>       | 1            |
| [10-15>      | 0            |
| 15 or more   | 1            |
+--------------+--------------+

对于 session_id 1,2 和 3 ,它们的访问时间大于等于 0 分钟且小于 5 分钟。
对于 session_id 4,它的访问时间大于等于 5 分钟且小于 10 分钟。
没有会话的访问时间大于等于 10 分钟且小于 15 分钟。
对于 session_id 5, 它的访问时间大于等于 15 分钟。

解法

SQL

(
    SELECT
        '[0-5>' AS bin,
        SUM(
            CASE
                WHEN duration / 60 < 5 THEN 1
                ELSE 0
            END
        ) AS total
    FROM Sessions
)
UNION
(
    SELECT
        '[5-10>' AS bin,
        SUM(
            CASE
                WHEN (duration / 60 >= 5 AND duration / 60 < 10) THEN 1
                ELSE 0
            END
        ) AS total
    FROM Sessions
)
UNION
(
    SELECT
        '[10-15>' AS bin,
        SUM(
            CASE
                WHEN (duration / 60 >= 10 AND duration / 60 < 15) THEN 1
                ELSE 0
            END
        ) AS total
    FROM Sessions
)
UNION
(
    SELECT
        '15 or more' AS bin,
        SUM(
            CASE
                WHEN duration / 60 >= 15 THEN 1
                ELSE 0
            END
        ) AS total
    FROM Sessions
);