Question

我有一个这样的数据库：

custNum         date        purchase        dayOfWeek
  333         2001-01-01    23.23            1
  333         2001-03-04    34.56            5
  345         2008-02-02    22.55            3
  345         2008-04-05    12.35            6
  ...          ...           ...            ...

我正在尝试为每个客户获取dayOfWeek列的模式（最常出现的值）。基本上，这将是每个客户购买最多的一周中的一天。像：

custNum         max(count(dayofweek(date)))
 333                   5
 345                   3
 356                   2
 388                   7
 ...                  ...

任何帮助都会非常感谢。

Answer 1

select custNum, dayOfWeek
from tableName t
group by custNum, dayOfWeek
having dayOfWeek = (
    select dayOfWeek
    from tableName
    where custNum = t.custNum
    group by dayOfWeek
    order by count(*) desc, dayOfWeek
    limit 1
)

MySQL找到多个子集的模式

1 个答案: