리트코드 : 1741. Find Total Time Spent by Each Employee

리트코드 : 1741. Find Total Time Spent by Each Employee

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문제

Table: Employees

+-------------+------+
| Column Name | Type |
+-------------+------+
| emp_id      | int  |
| event_day   | date |
| in_time     | int  |
| out_time    | int  |
+-------------+------+
(emp_id, event_day, in_time) is the primary key (combinations of columns with unique values) of this table.
The table shows the employees' entries and exits in an office.
event_day is the day at which this event happened, in_time is the minute at which the employee entered the office, and out_time is the minute at which they left the office.
in_time and out_time are between 1 and 1440.
It is guaranteed that no two events on the same day intersect in time, and in_time < out_time.


Write a solution to calculate the total time in minutes spent by each employee on each day at the office. Note that within one day, an employee can enter and leave more than once. The time spent in the office for a single entry is out_time - in_time.

Return the result table in any order.

The result format is in the following example.



Example 1:

Input: 
Employees table:
+--------+------------+---------+----------+
| emp_id | event_day  | in_time | out_time |
+--------+------------+---------+----------+
| 1      | 2020-11-28 | 4       | 32       |
| 1      | 2020-11-28 | 55      | 200      |
| 1      | 2020-12-03 | 1       | 42       |
| 2      | 2020-11-28 | 3       | 33       |
| 2      | 2020-12-09 | 47      | 74       |
+--------+------------+---------+----------+
Output: 
+------------+--------+------------+
| day        | emp_id | total_time |
+------------+--------+------------+
| 2020-11-28 | 1      | 173        |
| 2020-11-28 | 2      | 30         |
| 2020-12-03 | 1      | 41         |
| 2020-12-09 | 2      | 27         |
+------------+--------+------------+
Explanation: 
Employee 1 has three events: two on day 2020-11-28 with a total of (32 - 4) + (200 - 55) = 173, and one on day 2020-12-03 with a total of (42 - 1) = 41.
Employee 2 has two events: one on day 2020-11-28 with a total of (33 - 3) = 30, and one on day 2020-12-09 with a total of (74 - 47) = 27.

• 끝 시간 - 시작 시간을 구하고 날짜, 사원별로 구하기

문제 풀이

MySQL

WITH TEMP AS (
    SELECT EVENT_DAY, EMP_ID, OUT_TIME-IN_TIME AS TOTAL_TIME
    FROM EMPLOYEES
)

SELECT EMP_ID, EVENT_DAY AS `DAY`, SUM(TOTAL_TIME) AS TOTAL_TIME
FROM TEMP
GROUP BY EMP_ID, `DAY`

• CTE 하나 만들어서 출입시간 차이 계산해준다.
• 이후 GROUP BY + SUM

Pandas

import pandas as pd

def total_time(employees: pd.DataFrame) -> pd.DataFrame:
    employees['spend_time'] = employees['out_time']-employees['in_time']
    grouped = employees.groupby(['event_day','emp_id']).agg(
        total_time = ('spend_time','sum')
    ).reset_index()
    grouped.rename(columns={'event_day': 'day'}, inplace=True)
    return grouped

• 같은 방법으로 소요시간 컬럼 하나 할당해주기.
• 이후 group by + sum -> rename으로 정답 구하기

코멘트

• .