将两个选择的计数与子查询相除以获得百分比

Question

我已经写了这个查询，但是它说每个表都需要有自己的别名。我究竟做错了什么？据我所知，我已经对表进行了别名。

SELECT (a.total_complete_days / b.total_days) * 100 AS "% of complete days"
FROM
(SELECT COUNT(*) AS total_complete_days
FROM (
    SELECT email, job_date, SUM(job_minutes)
    FROM jobs
    GROUP BY email, job_date
    HAVING SUM(job_minutes) BETWEEN 200 and 1000
) a,
(SELECT COUNT(*) AS total_days
FROM (
    SELECT email, job_date, SUM(job_minutes)
    FROM jobs
    GROUP BY email, job_date
) b)

Answer 1

我想您可以将查询简化为

SELECT 
    (COUNT(CASE WHEN t.job_minutes_sum BETWEEN 200 and 1000 THEN 1 ELSE NULL END) / COUNT(*) 
    ) * 100 AS "% of complete days"
FROM (
    SELECT email, job_date, SUM(job_minutes) job_minutes_sum
    FROM jobs
    GROUP BY email, job_date
) t