如何从表中的同一记录列表中获取一条唯一记录?表中没有唯一约束 [英] How to get one unique record from the same list of records from table? No Unique constraint in the table

问题描述

我在 SQL Server 输出中有一个查询，

I have one query in SQL Server output,

假设我有一张表(Ex.StudentMaster)有一些字段——没有唯一约束.对于前.卷号和名称该表具有相同的数据.例如:

Suppose i have one table (Ex.StudentMaster) having some fields-No unique constraints. For Ex. RollNumber and Name The table has same same data. For ex:

RollNo      Name
    1       Yoko
    1       Yoko
    1       Yoko

我只想获得第三条记录.如何识别此唯一记录?

I want to get only third record. How can i identify this unique record?

推荐答案

任何一行都是第三行 :-)

Any row is a third row :-)

create table test
(
n int,
name varchar(30)
);

insert into test values(1,'yoko'),(1,'yoko'),(1,'yoko');

select ROW_NUMBER() over(order by name) as ordinal, * from test;

删除第三"行:-)

with a as
(
select ROW_NUMBER() over(order by name) as ordinal, * from test
)
delete from a where a.ordinal = 3

删除最后一行:

with a as
(
select ROW_NUMBER() over(order by name) as ordinal, * from test
)
delete from a where a.ordinal = (select MAX(ordinal) from a)

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