在HqlNamedParams中，如果條件不產生結果提取所有行

Question

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

這裏如果「值」不存在於表中，則獲取所有行。

我該怎麼做？

Answer 1

我誤解了這個問題，現在我編輯我的答案：

你必須運行兩個查詢。

// 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（但您使用更個性化的子查詢）

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);