Question

我是新手，我需要广告/营销机构数据库的帮助

我有两个表，一个是 List_of_billboards ，它具有三列：Billboard_ID（PK），位置和类型，第二个是 Billboard_Ad_Campaigns ，它具有四列：Ad_ID （PK），Cost_of_campaign，ID_of_client，Billboard_ID（FK）。

表中的数据如下：

表1：

Billboard_ID | Location     |  Type
BbID001      |    London    |  Digital
BbID002      |    Hayward   |  3D
BbID003      |    Las Vegas |  Painted
BbID004      |    New York  |  Painted

表2：

Ad_ID   |  Cost_of_campaign | ID_of_client | Billboard_ID
BbCID0001    $123               001            BbID001       
BbCID0002    $456               002            BbID002       
BbCID0003    $789               003            BbID003       
BbCID0004    $1234              003            BbID004

我如何找到某种广告牌（3D，数字，绘画等）的最高/最低成本？

例如，根据上述数据，涂漆成本最高的广告牌将是BbID004（纽约为一）

Answer 1

使用窗口功能。对于最便宜的广告系列：

select b.*
from (select t2.*,
             row_number() over (partition by t1.type order by t2.cost_of_campaign asc) as seqnum
      from table1 t1 join
           table2 t2
           on t1.Billboard_ID = t2.Billboard_ID
     ) b
where seqnum = 1

Answer 2

select t1.type,
       max(t2.cost_of_campaign) max_cost_of_campaign,
       min(t2.cost_of_campaign) min_cost_of_campaign
from table1 t1 
join table2 t2
on t1.Billboard_ID = t2.Billboard_ID
group by t1.type

https://dbfiddle.uk/?rdbms=sqlserver_2019&fiddle=5abc548aa178a82a9f6f33527fa5c265

或者如果需要，可以使用窗口函数和first_value来获取max和min中的其他列

select distinct t1.type,
       first_value(t1.Billboard_ID) over (partition by t1.type order by t2.cost_of_campaign desc) max_Billboard_ID,
       max(t2.cost_of_campaign) over (partition by t1.type) max_cost_of_campaign,
       first_value(t1.Billboard_ID) over (partition by t1.type order by t2.cost_of_campaign asc) min_Billboard_ID,
       min(t2.cost_of_campaign) over (partition by t1.type) min_cost_of_campaign
from table1 t1 
join table2 t2
on t1.Billboard_ID = t2.Billboard_ID

https://dbfiddle.uk/?rdbms=sqlserver_2019&fiddle=887b95cb041b1d6fb37ccfb47aabd3ea

通过SQL中两个不同表的数据查找最高/最低值

2 个答案: