如何在SQL中将多个聚合结果分组

Question

我有一个查询，该查询返回ID，用户所在的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;

如何查询数据库，以便获得总数相同但价值最高的唯一用户总数？

Answer 1

您可以获得按所需值分组的count（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

或用于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，最高级别

 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

您也可以尝试

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