Question

假设我有一张表，如下所示：

UserID    Meh    Meh //meh is some column
````````````````````
01        ...    ...
01        ...    ...
03        ...    ...
05        ...    ...
05        ...    ...
01        ...    ...
03        ...    ...

所以我想计算每个用户ID在此表中出现的次数。我现在正在这样做：

select UserId from NinjaTable group by UserId

但它给了我一些我不懂或不懂的东西。我希望结果如此：

UserID    Frequency
```````````````````
01        3
03        2
05        2

Answer 1

你快到了。

您正在分组，只需将计数添加到select子句。

select UserId, COUNT(*) from NinjaTable group by UserId order by COUNT(*) desc

应该真的这样做。

编辑：感谢@abe指点订单。

Answer 2

尝试类似：

select UserId, count(*) as Frequency from NinjaTable group by UserId

如果你愿意，可以点击order by UserId。

Answer 3

尝试

select UserID, Count(*) 
from theTable 
group by UserID

Answer 4

我认为你真正想要使用的是COUNT函数：

SELECT UserID, COUNT(*) AS Frequency FROM NinjaTable GROUP BY UserID

Answer 5

您可以使用group by语句：

SELECT UserId, COUNT(1) FROM MyTable GROUP BY UserId ORDER BY COUNT(1) DESC

这会将所有用户ID分组，找到行数（频率为你），然后按频率降序对结果集进行排序。

计算sql中所有项目的频率

5 个答案: