SQL Server 2022

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

create table t(name varchar(50), id Int)
insert into t select 'abc', 1
insert into t select null, 2
insert into t select null, 5
insert into t select null, 9
insert into t select '123', 12
insert into t select null, 14
insert into t select null, 15
insert into t select 'def', 16
insert into t select null, 18
insert into t select null, 19
insert into t select null, 22
insert into t select null, 25
12 rows affected

select * from t;


name
id


abc
1

null
2

null
5

null
9

123
12

null
14

null
15

def
16

null
18

null
19

null
22

null
25


update t set 
  name = NewName
from (
	select *, (
		select top(1) name 
		from t t2
		where t2.name is not null and t2.id < t.id
		order by id desc
	) NewName
	from t
	where name is null
)t;
9 rows affected

select * from t;


name
id


abc
1

abc
2

abc
5

abc
9

123
12

123
14

123
15

def
16

def
18

def
19

def
22

def
25

name	id
abc	1
null	2
null	5
null	9
123	12
null	14
null	15
def	16
null	18
null	19
null	22
null	25