How to get the only numeric part from a string SQL?

How to get the only numeric part from a string SQL?

Please check with this code, I was used in my project for extracting numeric value

DECLARE @string varchar(100)

SET @string = 'sk123;fja4567afj;as8901sfsfsfa2'

WHILE PATINDEX('%[^0-9]%',@string) <> 0

SET @string = STUFF(@string,PATINDEX('%[^0-9]%',@string),1,'')

SELECT @string  

   
OUTPUT= '123456789012'