如何从表的相同记录列表中获取一个唯一记录？表中没有唯一性约束

Question

我在SQL Server输出中有一个查询，

假设我有一个具有某些字段的表（Ex.StudentMaster）-没有唯一约束。对于前 RollNumber和Name该表具有相同的数据。例如：

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？

Answer 1

任何一行都是第三行:-)

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)