SQL 服务器复杂案例

Question

我找不到一种方法来为与此示例类似的内容创建案例。我援引他的知识！我每个月都会收到新奇的东西，字母从 A 到 E，我需要在每个客户礼物的大字母中写上 0。因此，如果我只收到 B，则 B=0，如果我收到 A 和 B，则 A=1 且 B=0，如果我收到 A、B、C，则 A=1、B=1 且 C=0，如果我收到 A 和 C，然后 A=1 和 C=0，由客户分组。

Customer Codes
111      A    
111      B    
111      C    
222      A        
222      B    
333      A

Answer 1

In the below SQl you're doing some row number functions and then ordering by the highest row number. After that you do another row number function by the highest row_number it gets in the cte.

With myCte
as
(
Select Customer,Code,Row_Number() OVER (PARTITION BY Customer Order By Code) rn
from myTable

)
select Customer,Code,
Case when rn2 = 1 then 0
else 1
end as myArbitraryNumber
 from
(
select Customer, Code, rn, Row_Number() OVER (Partition by Customer,rn Order by rn DESC) rn2 
from myCte
)

SQL 服务器复杂案例

SQL Server Complex Case

sql

sql-server-2008

function

case

case-when