Added as answer as requested...
Dates don't have formats in SQL Server, how you display them is the format. Strings have formats.
You can use FORMAT or CONVERT depending on your version.
convert(varchar(8),yourColumn,112)
format(yourCOlumn,'yyyyMMdd')
DEMO
declare @table table (yourColumn datetime)
insert into @table
values
(getdate())
select
yourColumn
,format(yourColumn,'yyyyMMdd')
,convert(varchar(8),yourColumn,112)
from @table
If your column is a string, then you need to convert that to a date first or just parse it a different way.
select
convert(varchar(8),cast('1/24/2018 10:34:23 PM' as datetime),112)
,format(cast('1/24/2018 10:34:23 PM' as datetime),'yyyyMMdd')