Php 用于每日汇总数据的SQL查询

我使用以下SQL查询从MySQL数据库获取数据

select
    classid,start,
    count(case when classid='Handball' then 1 end) as handball_count
from signature where classid='Handball'
group by start

例如，日期为2016.12.01。10:51:58格式

---

它应该每天进行，例如

2016.12.01。10:51:58

和

2016.12.01。15:51:58

在此查询中不应是其他条目。我应该怎样分组？我想对每天每项活动的参与者进行总结，不以参与者签名的日期分隔。

请将

日期时间

转换为

日期

     SELECT CONVERT(date, date)
or
GROUP BY CAST(date AS DATE)


select
    classid,CONVERT(date, date),
    count(case when classid='Handball' then 1 end) as handball_count
from signature where classid='Handball'
group by date,classid

---

请将

datetime

转换为

date

     SELECT CONVERT(date, date)
or
GROUP BY CAST(date AS DATE)


select
    classid,CONVERT(date, date),
    count(case when classid='Handball' then 1 end) as handball_count
from signature where classid='Handball'
group by date,classid

你可以试试这个

SELECT count(case when classid='Handball' then 1 end) as handball_count,
   classid,DATE(start) DateOnly 
FROM signature where classid='Handball'
GROUP BY DateOnly;

你可以试试这个

SELECT count(case when classid='Handball' then 1 end) as handball_count,
   classid,DATE(start) DateOnly 
FROM signature where classid='Handball'
GROUP BY DateOnly;

---

我正在考虑将

start

作为您的日期字段，因此这可能会对您有所帮助

select
    classid,CONVERT(start, date),
    count(case when classid='Handball' then 1 end) as handball_count
from signature where classid='Handball'
group by start

另外，您的日期格式与标准timestam不匹配，请查看。可能下面的参考资料也可以帮助你

select
    classid,CONVERT(start, date),
    count(case when classid='Handball' then 1 end) as handball_count
from signature where classid='Handball'
group by start

---

我正在考虑将

开始

作为您的日期字段，因此这可能会对您有所帮助

select
    classid,CONVERT(start, date),
    count(case when classid='Handball' then 1 end) as handball_count
from signature where classid='Handball'
group by start

另外，您的日期格式与标准timestam不匹配，请查看。可能下面的参考资料也可以帮助你

select
    classid,CONVERT(start, date),
    count(case when classid='Handball' then 1 end) as handball_count
from signature where classid='Handball'
group by start

---

您可以将日期时间强制转换为日期。您使用的是MySQL还是SQL Server？而且，这些时间戳似乎没有任何标准格式。它们是什么类型的？您可以将日期时间强制转换为日期。您使用的是MySQL还是SQL Server？而且，这些时间戳似乎没有任何标准格式。它们是什么类型的？