Oracle: http://docs.oracle.com/cd/B19306_01/server.102/b14200/sql_elements003.htm#BABGIGCJ PostgreSQL: http://www.postgresql.org/docs/9.1/static/datatype-datetime.html MySQL: http://dev.mysql.com/doc/refman/5.0/en/date-and-time-literals.html DB2 v9.5 http://www-01.ibm.com/support/knowledgecenter/SSEPGG_9.5.0/com.ibm.db2.luw.sql.ref.doc/doc/r0000731.html?lang=ja