If the format is always 3 char followed by 5 numeric can you just get the right 5 characters?

DECLARE @tbSample TABLE(Code VARCHAR(10))

INSERT INTO @tbSample SELECT 'SDH00151'

INSERT INTO @tbSample SELECT 'SDH00152'

INSERT INTO @tbSample SELECT 'SDH00153'

SELECT

Code

,RIGHT(Code,5) AS CodeNum

FROM

@tbSample