原生sql org.hibernate.exception.DataException: could not execute query

Could not open Hibernate Session for transaction

org.springframework.dao.DataIntegrityViolationException: could not execute query; SQL [select to_char(apply_time,'yyyy-mm') as time,sum(approve_quota) as total from APPLY_INFO group by to_char(apply_time,'yyyy-mm') order by to_char(apply_time,'yyyy-mm');]; nested exception is org.hibernate.exception.DataException: could not execute query

public List nonPerforming() {

		return getHibernateTemplate().execute(

				new HibernateCallback<List>() {

					@Override

					public List doInHibernate(Session session)

							throws HibernateException, SQLException {

						SQLQuery query = session

								.createSQLQuery("select to_char(apply_time,'yyyy-mm') as time," +

										"sum(approve_quota) as total from APPLY_INFO " +

										"group by to_char(apply_time,'yyyy-mm') " +

										"order by to_char(apply_time,'yyyy-mm');");

						List results = query.list();

						return results;

					}

				});

	}