mysql - 计算子查询 SQL 的百分比

Question

我有一个表记录有关电子邮件事件的事件。我想计算出在该事件中发生了多个事件的事件所占的百分比。

首先，我计算了每个事件中发生的事件数量:

select count(*) as counter
               from campaigns_log
               where event IN ('send', 'open')
                 and campaign_id is not null
               group by campaign_id, email

然后，我根据是否发生多个事件对营销事件进行分组:

select count(counter) as occurences, IF(counter > 1, 2, 1) as grouper
         from (select count(*) as counter
               from campaigns_log
               where event IN ('send', 'open')
                 and campaign_id is not null
               group by campaign_id, email) as counters_table
         group by grouper

结果示例:

occurences ¦ grouper
132        ¦ 1
360        ¦ 2

现在我想计算每一行的总出现次数的百分比。所以像这样:

occurences ¦ grouper ¦ percentage
132        ¦ 1       ¦ 132/(132+360)
360        ¦ 2       ¦ 360/(132+360)

我尝试了这个，但它不起作用，它无法正确计算总和:

select *, occurences/(select sum(occurences))
from (
         select count(counter) as occurences, IF(counter > 1, 2, 1) as grouper
         from (select count(*) as counter
               from campaigns_log
               where event IN ('send', 'open')
                 and campaign_id is not null
               group by campaign_id, email) as counters_table
         group by grouper
     ) as occurences_table group by occurences, grouper

知道我最后一步的错误在哪里吗？

Answer 1

使用子查询进行总数和除法

select a.occurences,a.grouper, (a.occurences/c.total) as percentage
from (select count(counter) as occurences, IF(counter > 1, 2, 1) as grouper
             from (select count(*) as counter
                   from campaigns_log
                   where event IN ('send', 'open')
                     and campaign_id is not null
                   group by campaign_id, email) as counters_table
             group by grouper
   ) a,
    (select sum(occurences) total from
    (select count(counter) as occurences, IF(counter > 1, 2, 1) as grouper
             from (select count(*) as counter
                   from campaigns_log
                   where event IN ('send', 'open')
                     and campaign_id is not null
                   group by campaign_id, email) as counters_table
             group by grouper
   ) b )c