problem with function TRIM

I have a database that contains some columns with multiple values separated with comma . So I'm trying to use a combination of case, substring and trim to split these values into multiple colums.

The following statement part does not work:

case when pos2 = 0 then trim(substring(Description, pos1+1))
end as bed

TEIID31100 Parsing error: Encountered "+1)[*])[*] end as" at line 3, column 68.

If I add ' ' FROM to the trim statement it does work and returns a correct result.

working statement:

case when pos2 = 0 then trim(' ' FROM substring(Description, pos1+1))
end as bed