Spring JPA或规范中的Union
正在尝试为下面的查询创建条件生成器。然而,JPA似乎不支持该联盟。有什么想法吗Spring JPA或规范中的Union,spring,hibernate,spring-data-jpa,criteria-api,jpa-criteria,Spring,Hibernate,Spring Data Jpa,Criteria Api,Jpa Criteria,正在尝试为下面的查询创建条件生成器。然而,JPA似乎不支持该联盟。有什么想法吗 SELECT * FROM firsttable i1 WHERE EXISTS (SELECT 1 FROM secondtable WHERE id = i1.fid AND flag = 'Flag1') AND EXISTS (SELECT 1
SELECT *
FROM firsttable i1
WHERE EXISTS (SELECT 1
FROM secondtable
WHERE id = i1.fid
AND flag = 'Flag1')
AND EXISTS (SELECT 1
FROM secondtable
WHERE id = i1.fid
AND flag = 'Flag2')
UNION
SELECT *
FROM firsttable i1
WHERE NOT EXISTS (SELECT 1
FROM secondtable
WHERE id = i1.fid
AND flag = 'Flag1')
AND EXISTS (SELECT 1
FROM secondtable
WHERE id = i1.fid
AND flag = 'Flag2');
有多种方法可以模仿
联合
。运行两个单独的查询并合并结果,在DB端创建一个视图并将其用于检索,将查询条件组合为条件1或条件2,谢谢。我也在考虑视图方法,但我真的需要为紧急交付执行此任务,我在想JPA中是否有某种方法或标准以某种方式完成此任务。