Question

我遇到了SQL OLAP多维数据集问题，但没有得到想要的输出。我现在在执行代码时得到0行。

问题：对于每个城镇，找到数量最多的产品ID。

下面是我的代码：

SELECT [supplier town], [product id], [quantity]
FROM my_cube
WHERE "supplier town" is not null
AND "supplier name" is not null
GROUP BY [supplier town], [product id], [quantity]
HAVING [quantity] >= ALL(
   SELECT [quantity]
   FROM my_cube)

这里是没有我的代码的第二/底部的输出= GROUP BY，HAVING。

预先感谢

Answer 1

这有效，请参见下面的结果。请注意，麦迪逊/天然气的数据仅为200000，史蒂文斯波因特（Stevens Point）有两种相同数量的产品，并且添加了Wausau。

SELECT [supplier town], [product id], [quantity]
FROM my_cube aa
WHERE "supplier town" is not null
--AND "supplier name" is not null
GROUP BY [supplier town], [product id], [quantity]
HAVING [quantity] >= ALL(
   SELECT [quantity]
   FROM my_cube bb where aa.[supplier town] = bb.[supplier town])

supplier town   product id  quantity
Chicago         Computer    1010
Madison         Gas         200000
Springfield     Computer    100
Stevens Point   Airplane    110000
Stevens Point   Computer    110000
Wausau          Boat        200100

Answer 2

通过使用SQL排名函数，可以更轻松地解决此问题。例如...

drop table if exists #data;

create table #data(
    city nvarchar(100) ,
    product nvarchar(100) ,
    quantity int
);

insert  #data
values  ('Chicago', 'Airplane', 1000) ,
        ('Chicago', 'Boat', 10) ,
        ('Chicago', 'Computer', 1010) ,
        ('Stevens Point', 'Computer', 100) ,
        ('Stevens Point', 'Airplane', 110000) ,
        ('Stevens Point', 'Computer', 110000)
;


select  city ,
        product ,
        quantity ,
        row_number() over (partition by city order by quantity desc, product desc) as [order]
from    #data

如果您只想为每个城市选择排名靠前的城市，那么最终查询会稍微复杂一些，但还不错...

select  *
from    (
    select  city ,
            product ,
            quantity ,
            row_number() over (partition by city order by quantity desc, product desc) as [order]
    from    #data
) x
where   x.[order] = 1

...或者如果您想看中并使用CTE的...

with
    x as (
        select  city ,
                product ,
                quantity ,
                row_number() over (partition by city order by quantity desc, product desc) as [order]
        from    #data
    )
select * from x where [order] = 1

sql：在多维数据集中找到最大的数字

2 个答案: