可以用查詢的方式去新增..

declare @Test table(
	Test_ID int
	,Test_Txt nvarchar(5)
	,Test_Count int
)

insert into @Test
select Set_ID
,Set_Txt
,isNull((select count(*) from @Test where Set_ID >= Test_ID and Set_Txt = Test_Txt),0)+1 as Set_Count
from (
	select isNull((select max(Test_ID) from @Test),0) + 1 as Set_ID
	,'A' as Set_Txt
) as k

insert into @Test
select Set_ID
,Set_Txt
,isNull((select count(*) from @Test where Set_ID >= Test_ID and Set_Txt = Test_Txt),0)+1 as Set_Count
from (
	select isNull((select max(Test_ID) from @Test),0) + 1 as Set_ID
	,'B' as Set_Txt
) as k

insert into @Test
select Set_ID
,Set_Txt
,isNull((select count(*) from @Test where Set_ID >= Test_ID and Set_Txt = Test_Txt),0)+1 as Set_Count
from (
	select isNull((select max(Test_ID) from @Test),0) + 1 as Set_ID
	,'C' as Set_Txt
) as k

insert into @Test
select Set_ID
,Set_Txt
,isNull((select count(*) from @Test where Set_ID >= Test_ID and Set_Txt = Test_Txt),0)+1 as Set_Count
from (
	select isNull((select max(Test_ID) from @Test),0) + 1 as Set_ID
	,'B' as Set_Txt
) as k

insert into @Test
select Set_ID
,Set_Txt
,isNull((select count(*) from @Test where Set_ID >= Test_ID and Set_Txt = Test_Txt),0)+1 as Set_Count
from (
	select isNull((select max(Test_ID) from @Test),0) + 1 as Set_ID
	,'C' as Set_Txt
) as k

insert into @Test
select Set_ID
,Set_Txt
,isNull((select count(*) from @Test where Set_ID >= Test_ID and Set_Txt = Test_Txt),0)+1 as Set_Count
from (
	select isNull((select max(Test_ID) from @Test),0) + 1 as Set_ID
	,'C' as Set_Txt
) as k

select * from @Test

一般來說是不太可能直接這樣用。
只能利用後端程式，來寫程式處理。或是sql的事件功能函式來幫你處理了。
當然用「純真的人」給你用的方式也是一種方法。

其實這方法只是利用了sql來寫程式處理。也算是一招就是了。

我的作法是這樣：
1.先建一個函數GetSNCount(假設Table Name是dbo.test)

CREATE FUNCTION [dbo].[GetSNCount](@SN varchar(10))  

RETURNS  int
AS
BEGIN
	Declare @SNCount int = 0
	SELECT @SNCount=count(SN) from dbo.test where SN=@SN group by SN

	set @SNCount = @SNCount + 1
	-- Return the result of the function
	RETURN @SNCount

END

2.Insert測試資料

insert test(sn,[count]) values('A',dbo.getSNCount('A'))
insert test(sn,[count]) values('B',dbo.getSNCount('B'))
insert test(sn,[count]) values('C',dbo.getSNCount('C'))
insert test(sn,[count]) values('B',dbo.getSNCount('B'))
insert test(sn,[count]) values('C',dbo.getSNCount('C'))
insert test(sn,[count]) values('C',dbo.getSNCount('C'))

3.結果如下

感謝您的詢問。 MS SQL Server 中如果不將該列設為主鍵，則無法直接基於另一列實作自增。 但是，您可以透過使用基於所需列遞增值的序列或觸發器來實現類似的功能。 至於rice purity test，它是一種有趣而輕鬆的方式來衡量一個人的純真或生活各個方面的經歷。 這是一個流行的網路測驗，涵蓋從個人行為到浪漫關係的廣泛主題。

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