彙總/計數行

Question

我有一個表，如：

Create Table SalesTable 
(StuffID int identity not null, 
    County geography not null, 
    SaleAmount decimal(12,8) not null, 
    SaleTime datetime not null) 

它有量，時間每銷售的記錄，和縣，出售發生的地理在

我想運行這樣的查詢：

Select sum(SaleAmount), County from SalesTable group by County 

但如果我嘗試這樣做，我得到：

The type "geography" is not comparable. It cannot be used in the GROUP BY clause. 

但是我想知道每個縣有多少銷售額。令人煩惱的是，如果我將縣級縮寫（SDC，LAC，SIC等），那麼我可以將它們分組，因爲它只是一個varchar。但由於其他原因，我使用了地理數據類型。

Answer 1

有一個功能與地理類型爲char工作

試試這個

Select sum(SaleAmount), County.STAsText() from SalesTable 
group by County.STAsText() 

Answer 2

我會提出一個稍微不同的結構：

create table dbo.County (
    CountyID int identity not null 
    constraint [PK_County] primary key clustered (CountyID), 
    Name varchar(200) not null, 
    Abbreviation varchar(10) not null, 
    geo geography not null 
); 
Create Table SalesTable 
( 
    StuffID int identity not null, 
    CountyID int not null 
    constraint FK_Sales_County foreign key (CountyID) 
    references dbo.County (CountyID), 
    SaleAmount decimal(12,8) not null, 
    SaleTime datetime not null 
); 

從那裏，你總看起來像：

Select c.Abbreviation, sum(SaleAmount) 
from SalesTable as s 
join dbo.County as c 
    on s.CountyID = c.CountyID 
group by c.Abbreviation; 

如果您確實需要聚合中的地理位置列，那麼您需要將子查詢或公用表格表示爲：

with s as (
    Select c.CountyID, c.Abbreviation, 
     sum(s.SaleAmount) as [TotalSalesAmount] 
    from SalesTable as s 
    join dbo.County as c 
     on s.CountyID = c.CountyID 
    group by c.Abbreviation 
) 
select s.Abbreviation, s.geo, s.TotalSalesAmount 
from s 
join dbo.County as c 
    on s.CountyID = s.CountyID;