You'll have better performance if you change the following statement

WHERE SD.Code IS NOT NULL AND RTRIM(LTRIM(SD.Code ))<>''

with

WHERE SD.Code <> ''

The results are the same and you can test them if you want.

Here's a script.

DECLARE @Tabletable(

mystringchar(15))

INSERT @Table

VALUES( ''),( ' '),( ' '),

( 'a'),( ' b'),( 'c '),

( ' '), (NULL)

SELECT * FROM @Table

WHERE mystring <> ''