Resultset Mapping Returns null, SQL statement doesn't

I have an SQL statement like this:

SELECT generatedresult,sum(size) as count  FROM table1_detail AS w WHERE date > '2011.06.01' AND w.l_date < '2011.06.02'  GROUP BY category ORDER BY count  desc ; 

Which returns:

generatedresult  |   count    
------------------+------------
                  | 3743040708
 Phrase1          |    1332377
 Phrase2          |          0
 Phrase3          |          0

When I write a resultset mapping for this query like this:

@Entity
@S开发者_运维技巧tateless
@Cache(type = CacheType.NONE, alwaysRefresh=true, shared=false, expiry=1, size=0)
@Cacheable(false)
@SqlResultSetMappings({
    @SqlResultSetMapping(name = "ResultMapping",
    entities = {
        @EntityResult(entityClass = ResultMap.class,
        fields = {
            @FieldResult(name = "generatedresult", column = "generatedresult"),
            @FieldResult(name = "count", column = "count")
        })})
})

and use it in another class I got null result. Does anyone having any opinion about this issue?