DB2DATE类型获取最小值

在db2中有个字段是date类型，如何取最小值？有null值的话怎么让它不显示null值，只显示最小值

try
select dateFiled from t where not(dateFiled is NULL) order by dateFiled asc limit 1;
or
select min(dateFiled) from t where not(dateFiled is NULL) ;