[LeetCode][SQL50] #10. Average Time of Process per Machine

💻 문제 주소 : Average Time of Process per Machine - LeetCode

Average Time of Process per Machine - LeetCode

 

💻 문제

The resulting table should have the machine_id along with the average time as processing_time, which should be rounded to 3 decimal places. Return the table in any order.

- machine_id별 평균 processing_time을 구하시오. processing_time은 소수점 세 자리수까지 출력되어야 하며, 출력 순서는 상관 없습니다.

 

* processing_time : (end timestamp - start timestamp)

 

💻 코드 및 풀이 

select a1.machine_id, round(avg(a2.timestamp-a1.timestamp), 3) as processing_time
from Activity a1, Activity a2
where a1.machine_id = a2.machine_id and a1.process_id = a2.process_id and a1.activity_type = 'start' and a2.activity_type = 'end'
group by a1.machine_id