关于ofbiz的一个问题

select * from table where field1>field2 怎么实现啊

我用如下代码，不行，不知道为什么
GenericDelegator delegator = GenericDelegator.getGenericDelegator("default");
List exprlist = new ArrayList();

EntityExpr expr = new EntityExpr("field1",EntityOperator.LESS_THAN ,"field2");

exprlist.add(expr);

try {
list = delegator.findByCondition("table",
exprlist,
selectList);
} catch (GenericEntityException e) {
e.printStackTrace();
}