mysql - 值的平均值 - Mysql

Question

我有一个sql查询如下:

SELECT COUNT(*)
FROM event_db.event_log el, event_db.event_type et
WHERE et.event_type_id = el.event_type_id AND et.name in ('kpi_stats_dumped') AND el.timestamp > str_to_date('2016,12,12','%Y,%m,%d') AND el.timestamp < str_to_date('2017,12,12','%Y,%m,%d')
GROUP BY et.name, date_format(el.timestamp, '%d-%m-%Y')
ORDER BY et.name, el.timestamp

返回结果如下:

1440
1441
1546
1234
1235
33
224

我需要找到所列值的平均值。(1021.85714286)

谁能帮我做同样的事情。

Answer 1

select avg(cnt) as average_count
from 
(
    SELECT COUNT(*) as cnt
    FROM event_db.event_log el
    JOIN event_db.event_type et ON et.event_type_id = el.event_type_id
    WHERE et.name in ('kpi_stats_dumped') 
    AND el.timestamp > str_to_date('2016,12,12','%Y,%m,%d') 
    AND el.timestamp < str_to_date('2017,12,12','%Y,%m,%d')
    GROUP BY et.name, date_format(el.timestamp, '%d-%m-%Y')
) tmp