Fill empty values based on the value in previous rows

Fill-empty-values-in-the-dataset.sql

declare @temp as table (
DayDate date not null,
Inventory int null
)

insert into @temp
values 
('01-01-2022', 1234),
('02-01-2022', null),
('03-01-2022', null),
('04-01-2022', 2345),
('05-01-2022', null),
('06-01-2022', 3456),
('07-01-2022', null),
('08-01-2022', null)

select * from @temp

declare @previousValue int

 UPDATE @temp 
SET 
    @previousValue = COALESCE(Inventory, @previousValue),
    Inventory = COALESCE(Inventory, @previousValue)

select * from @temp