Code:
select * from
   ( select SUBSTR(DIGITS(PAUSTRITT), 5, 4) CONCAT                      
            SUBSTR(DIGITS(PAUSTRITT), 3, 2) CONCAT 
            SUBSTR(DIGITS(PAUSTRITT), 1, 2)
        AS AUSTRITT from hdscw/hansalf1) x 
   where austritt > '00000000'