SQL 服务器：多列的唯一值总和

Question

使用 SQL 服务器，我有一个 table，如下例 table 所示。我需要每个列的所有唯一值的总和 "BookOrder, StationaryOrder, and Printing Order"。

样本 TABLE:

KeyIDCustomer   BooksOrder  StationaryOrder PrintingOrder
29945843         1070756    1891514            198876
29945843         1070756    1893827            198876
29945843         1070758    1891514            198876
29945843         1070758    1893827            198876

我正在使用下面的代码来实现这个目标。

Select DISTINCT KeyIDCustomerID,
Sum(Case when BooksOrder is not null then 1 else 0 End) TotalBookOrders,  
Sum(Case when StationaryOrder is not null then 1 else 0 End) TotalStationaryOrder,
Sum(Case when PrintingOrder is not null then 1 else 0 End)TotalPrintingOrder

使用此编码得到如下结果

  KeyIDCustomerID   TotalBookOrders TotalStationaryOrder    TotalPrintingOrder
   29945843                    4                       4                    4

我希望结果是这样的

  KeyIDCustomerID   TotalBookOrders TotalStationaryOrder    TotalPrintingOrder
   29945843                    2                       2                    1

有什么方法可以在 SQL 中实现这个目标？

谢谢

Answer 1

做一个group by，count(distinct column)来数：

Select KeyIDCustomerID,
       COUNT(distinct BooksOrder) TotalBookOrders,  
       COUNT(distinct StationaryOrder) TotalStationaryOrder,
       COUNT(distinct PrintingOrder) TotalPrintingOrder
from tablename
group by KeyIDCustomerID

Answer 2

我认为

的恰当用语

sum of all the unique values per the columns

是"count of unique values"

COUNT (DISTINCT column_name) returns column_name

中唯一的非空值的数量

Select 
KeyIDCustomerID,
COUNT(DISTINCT BooksOrder) as TotalBookOrders,  
COUNT(DISTINCT StationaryOrder) as TotalStationaryOrder,
COUNT(DISTINCT PrintingOrder) as TotalPrintingOrder
FROM SAMPLE_TABLE
GROUP BY KeyIDCustomerID

SQL 服务器：多列的唯一值总和

SQL Server: Sum of Unique values for multiple columns

sql

sql-server

sql-server-2008

sql-server-2008-r2

sql-server-2012