[英]SQL aggregation select using SUM and COUNT on different tables
我有一张桌子的电子邮件
id date sent_to
1 2013-01-01 345
2 2013-01-05 990
3 2013-02-05 1000
table2是响应
email_id email response
1 xyz@email.com xxxx
1 xyzw@email.com yyyy
.
.
.
我想要具有以下格式的结果:
Month total_number_of_subscribers_sent total_responded
2013-01 1335 2
.
.
这是我的查询:
SELECT
DATE_FORMAT(e.date, '%Y-%m')AS `Month`,
count(*) AS total_responded,
SUM(e.sent_to) AS total_sent
FROM
responses r
LEFT JOIN emails e ON e.id = r.email_id
WHERE
e.date > '2012-12-31' AND e.date < '2013-10-01'
GROUP BY
DATE_FORMAT(e.date, '%Y %m')
它可以与total_responded一起正常工作,但是total_sent变得疯狂了几百万,这显然是因为结果联接表具有冗余值。
因此,基本上可以在同一查询中对不同的表进行SUM和COUNT吗?
如果要计算每个表中的重复项,则查询有点复杂。
在将它们连接在一起之前,需要分别汇总发送和响应。 加入日期是日期,该日期必然来自“已发送”信息:
select r.`Month`, coalesce(total_sent, 0) as total_sent, coalesce(total_emails, 0) as total_emails,
coalesce(total_responses, 0) as total_responses,
coalesce(total_email_responses, 0) as total_email_responses
from (select DATE_FORMAT(e.date, '%Y-%m') as `Month`,
count(*) as total_sent, count(distinct email) as total_emails
from emails e
where e.date > '2012-12-31' AND e.date < '2013-10-01'
group by DATE_FORMAT(r.date, '%Y-%m')
) e left outer join
(select DATE_FORMAT(e.date, '%Y-%m') as `Month`,
count(*) as total_responses, count(distinct r.email) as total_email_responses
from emails e join
responses r
on e.email = r.email
where e.date > '2012-12-31' AND e.date < '2013-10-01'
) r
on e.`Month` = r.`Month`;
您的回复与“已发送”信息甚至日期都没有链接的明显事实表明您的操作和数据确实存在问题。
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