hql - 在 HqlNamedParams 中，如果 where 条件不产生结果，则获取所有行

Question

StringBuilder query = new StringBuilder("from country ");
query.append("and stateId in (:stateId)");
hqlNamedParam.addParamAndValue("stateId", values);

如果表中不存在“值”，则获取所有行。

我该怎么做？

Answer 1

我误解了这个问题，现在我编辑我的答案：

您必须运行两个查询。

// The first:

StringBuilder query = new StringBuilder("from country ");
query.append("and stateId in (:stateId)");
hqlNamedParam.addParamAndValue("stateId", values);

// The second (only if the first doesn't return rows)

if (outList == null || outList.size == 0) {
    StringBuilder query2 = new StringBuilder("from country ");
}

或者（但您使用更多带有计数的子查询）

StringBuilder query = new StringBuilder("from country ");
query.append(" where 
    (select count(c2.id) from country c2 where c2.stateid in (:stateId)) > 0
    and cs.stateid in (:stateId)
    or (select count(c3.id) from country c3 where c3.stateid in (:stateId)) = 0");
hqlNamedParam.addParamAndValue("stateId", values);