Question

category    item    Price   status
       A    Mobile1 1300    2
       A    Mobile1 1300    3
       A    Mobile1 1300    2
       B    Mobile1 1200    2
       B    Mobile1 1200    2
       A    Mobile2 2000    2
       A    Mobile2 2000    2
       B    Mobile2 1800    2
       B    Mobile2 1800    2
       C    Mobile2 1300    2
       A    Mobile3 3000    3
       B    Mobile3 2500    2
       C    Mobile3 2000    2
       A    Mobile3 3000    3

这是我想要的数据显示结果如：

category    Item    Price   Status  quantity
       A    Mobile1 1300    2       2
       A    Mobile2 2000    2       2
       B    Mobile3 2500    2       1

我在下面尝试了查询：

select  category, Item, Price, Status, count(Category) quantity from table1
where status = 2 and category = case category when 'A' then 'A' else 'B' End
group by category, Item, Price,Status

我试图显示A类的所有数据，如果A类物品数据不可用，则显示B类物品

Answer 1

您可以union all使用not in，如下所示：

select category, Item, Price, status, count(Category) quantity
from table1
where status = 2
    and category = 'A'
group by category, Item, Price, status

union all

select category, Item, Price, status, count(Category) quantity
from table1
where status = 2
    and category = 'B'
    and item not in (
        select item
        from table1
        where status = 2
            and category = 'A'
        )
group by category, Item, Price, status

Answer 2

您似乎想要优先考虑每个项目的类别。您可以使用dense_rank()作为优先级，然后使用聚合来获取所需类别的摘要：

select min(category) as category, item, avg(price) as price,
       max(status) as status, count(*)
from (select t1.*,
             dense_rank() over (partition by item
                                (case when category = 'A' then 1
                                      when category = 'B' then 2
                                      when category = 'C' then 3
                                      else 4
                                 end)
                                ) as seqnum
      from table1 t1
      where status = 2
     ) t1
where seqnum = 1
group by item;

如果类别A数据不可用，则显示类别B在SQL中

2 个答案: