It would be better to use DAY instead of DAYOFMONTH for portability.

Article:
The SQL Reference for Cross-Platform Development
http://www-128.ibm.com/developerwork...206sqlref.html

PDF Manual:
SQL Reference for Cross-Platform Development Version 3
(DB2 for: z/OS V9, iSeries V5R4, LUW V9)
ftp://ftp.software.ibm.com/ps/produc...S/cpsqlrv3.pdf