这是我的代码：

CriteriaBuilder cb = getEm().getCriteriaBuilder();
CriteriaQuery<Assignment> query = cb.createQuery(Assignment.class);
Root<Assignment> assignment = query.from(Assignment.class);

query.where(
    cb.equal(assignment.get("request"),request),cb.isNull(assignment.get("endDate")));

return getEm().createQuery(query).getResultList();

生成的查询是：

SELECT ASSX_ID,END_DATE,BEGIN_DATE,COMMENTS,ASSX_OER_ASSIGNED_TO_ID,OER_OER_ID_ASSIGNED_BY,ASSX_RQST_ID 
FROM TARTS.ASSIGNMENT_XREF 
WHERE (ASSX_RQST_ID = ?)

除了where子句外,它看起来不错.我期待：

SELECT ASSX_ID,ASSX_RQST_ID FROM TARTS.ASSIGNMENT_XREF 
WHERE (ASSX_RQST_ID = ? AND BEGIN_DATE IS NOT NULL)

如果我使用cb.and(arg1,arg2)也没关系.难道我做错了什么？任何帮助将不胜感激.