Question

SELECT
smart_curmonth_portals.portal_name,
COUNT(smart_curmonth_portals.portal_name) as Hits,
COUNT(smart_curmonth_portals.page_name is 'Home') as Home*******
COUNT(smart_curmonth_portals.page_name is not 'Home') as Subpage*******
COUNT(smart_curmonth_portals.page_name is NULL) as Downloads*******
FROM
smart_curmonth_portals
GROUP BY
smart_curmonth_portals.portal_name
ORDER BY
Hits DESC

我有一个表 - smart_curmonth_portals，我用它来报告用户点击数。我没有做分析报告 - 它的格式不好，所以我不能改变它。该表格如下：

portal_name - 目前正在对此进行COUNT并正常工作
page_name - 给出了一个人进入＃1门户网站时的确切页面。大多数情况下它是'Home'，有时它是一个具有随机名称的子页面，有时它是NULL并且转到＃3。
doctitle - ＃2上的NULL只是直接项目下载，每个都有名称 - 我们不需要，但我们需要计算。

想看看：

Portal_Name   Hits   Home   Subpages    Downloads
Testportal    3000   2300    600        100

Answer 1

COUNT(x)计算x不为空的次数。在您的查询中，它可能返回所有值的总行数（或接近它）。

如果您想要条件为真的行数，请使用sum()：

SELECT scp.portal_name,
       sum(scp.portal_name) as Hits,
       sum(scp.page_name = 'Home') as Home,
       sum(scp.page_name <> 'Home') as Subpage,
       sum(scp.page_name is NULL) as Downloads
FROM smart_curmonth_portals scp
GROUP BY scp.portal_name
ORDER BY Hits DESC ;

Answer 2

一般（不特定于MySQL）解决方案是：

select portal_name
    ,COUNT(portal_name) as Hits
    ,COUNT(case when page_name = 'Home' then 1 end) as Home
    ,COUNT(case when page_name <> 'Home' then 1 end) as Subpage
    ,COUNT(case when page_name is null then 1 end) as Downloads
from smart_curmonth_portals
group by portal_name
order by Hits desc

在mysql中排序多个COUNT个实例？

2 个答案: