如何在SQL中分组多个聚合结果

Question

我有一个查询返回用户所在的ID，最高值和最高级别的项目。

我的查询如下：

SELECT id, 
MAX(item) AS highest_item, 
MAX(level) AS highest_level 
FROM data 
GROUP BY 1 
ORDER BY 1; 

我如何可以查询数据库，这样我收到的唯一用户的总数，谁是在同一水平最高，并且具有相同价值最高的项目吗？

Answer 1

您可以根据您需要的值获得计数（distcint id）。例如。对于这两个值：

select count(distinct id), highest_item, highest_level 

    from ( 
    SELECT id, 
    MAX(item) AS highest_item, 
    MAX(level) AS highest_item 
    FROM data 
    GROUP BY 1 
) t 
group by highest_item, highest_level 
order by count(distinct id) desc 

或highest_item

select count(distinct id), highest_item 

    from ( 
    SELECT id 
    MAX(item) AS highest_item, 
    MAX(level) AS highest_level 
    FROM data 
    GROUP BY 1 
) t 
group by highest_item 
order by count(distinct id) desc 

的

为HIGHEST_LEVEL

select count(distinct id), highest_level 

    from ( 
    SELECT id, 
    MAX(item) AS highest_item, 
    MAX(level) AS highest_level 
    FROM data 
    GROUP BY 1 
) t 
group by highest_level 
order by count(distinct id) desc 

Answer 2

你可以试试这个也

Select id,count(Id) from data group by level,item having level=max(level) and item=max(item)