如何使用字段獲取所有最大數量

Question

我試圖用表中的最大條目數返回名稱，併爲那些count爲最大的返回（name，count）元組列表。我目前的解決方案使用：

select name, count(*) 
from action_log 
group by name 
order by count desc 
limit 1; 

的問題是，使用limit 1不考慮具有最大計數值多個名稱。

如何確定最大計數，然後獲得所有匹配的名稱？我想（但不能明顯地）做這樣的事情：

select name, max(count(*)) 
from action_log 
group by name; 

Answer 1

SQL Fiddle

with s as (
    select name, count(*) as total 
    from action_log 
    group by name 
), m as (
    select max(total) as max_total from s 
) 
select name, total 
from s 
where total = (select max_total from m) 

Answer 2

試試這個：

select name, COUNT(*) 
from action_log 
group by name 
HAVING COUNT(*) = (SELECT TOP 1 COUNT(*) from action_log group by name ORDER BY COUNT(*) DESC) 

Answer 3

你可以使用子查詢做到這一點 - 除了有圍繞該組的一些規則。如何以期簡化IT：

create view cname as 
    select name, count(name) c 
    from action_log 
    group by name 

然後SELECT這樣的：

select distinct a.name 
from action_log a 
    join cname c on c.name = a.name 
where c.c = (select max(c) from cname) 

，這裏是一個SQL Fiddle來證明這一點。

Answer 4

你可以用子查詢

做到這一點。例如：

SELECT MAX(cnt) FROM 
(SELECT name, count(*) AS cnt 
FROM action_log 
GROUP BY name) AS gb 

Answer 5

你可以用rank()功能做到這一點，所以你不必查詢表的多個次：

with cte as (
    select 
     name, count(*) as total, 
     rank() over(order by count(*) desc) as rnk 
    from action_log 
    group by name 
) 
select name, total 
from cte 
where rnk = 1 

更妙的是，你可以dense_rank()，所以你可以把N個組或採取n組：

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sql fiddle demo