Question

我有一个名为activity的表，它使用以下列：

LoginDate, LoginID, Department, IsMGR

我尝试了这个查询：

  SELECT COUNT(*), 
         DATE_FORMAT( LoginDate, '%m%d%Y' ) AS LogDate, 
         LoginID, Department
    FROM `activity` 
   WHERE IsMGR = '1' 
     AND LoginDate > '2011-01-01 00:00:00' 
GROUP BY LoginID, LogDate 
ORDER BY LoginID,LogDate DESC

我最终得到的是：

3   02172011    sdavis  accounting
1   02162011    sdavis  accounting
2   02132011    sdavis  accounting
1   02102011    sdavis  accounting
5   02092011    sdavis  accounting
4   02082011    sdavis  accounting
1   03182011    dmorris     marketing
1   03092011    dmorris     marketing
6   04142011    cchan   technology
1   03282011    cchan   technology
2   03262011    cchan   technology
2   03112011    cchan   technology
1   03102011    cchan   technology

这是计算他们登录的每一天的次数。我想要的是每天只计算一次，并且每个人的所有日期都计算在一起他们登录的日子，以及最后一天。使用上面的数据样本，我想要的输出应该是

6 02172011 sdavis accounting
2 03182011 dmorris marketing
5 04142011 cchan technology

所以我想要的是以某种方式将上述分组结果按第二组标准分组......？

Answer 1

试试这个：

SELECT COUNT(distinct LoginDate) AS NumLogins,
       DATE_FORMAT( MAX(LoginDate), '%m%d%Y' ) AS LastLogDate, 
       LoginID, Department
FROM activity 
WHERE IsMGR='1' AND LoginDate > '2011-01-01 00:00:00' 
GROUP BY LoginID, Department
ORDER BY LoginID, Department DESC

Answer 2

select
    count(distinct LoginDate) as loginCount,
    max(LoginDate) as lastLoginDate,
    LoginID,
    Department
FROM `activity` 
where IsMGR='1' 
and LoginDate > '2011-01-01 00:00:00' 
GROUP BY LoginID, Department 
ORDER BY LoginID, lastLoginDate DESC

MySQL Group By＆amp;数...我可以进行嵌套分组吗？

2 个答案: