Spring JPA 规范不存在且自连接

Question

如何在Spring JPA规范中构建以下SQL查询？

SELECT col1, col2, MAX(col3) 
FROM table_name t1 
WHERE col4 IN (1,2,3) AND status IN ('STATUS_1','STATUS_2') AND 
NOT EXISTS 
(
 SELECT 1 FROM table_name t2 WHERE t1.id = t2.parent_id 
 AND t2.status IN ('STATUS_3','STATUS_4')
)
GROUP BY col1, col2;

爪哇代码：

return new Specification<TableEntity>() {
    @Override
    public Predicate toPredicate(Root<TableEntity> root, CriteriaQuery<?> query, CriteriaBuilder builder) {
        // how to build Predicates for the above query which has self-join and not exists.
    }
};

Answer 1

试试这个

return new Specification<TableEntity>() {
    @Override
    public Predicate toPredicate(Root<TableEntity> root, CriteriaQuery<?> query, CriteriaBuilder builder) {
         Subquery<TableEntity> subquery = query.subquery(TableEntity.class);
         Root<TableEntity> subqueryRoot = subquery.from(TableEntity.class);
         subquery.select(subqueryRoot);
         subquery.where(builder.and(builder.equal(root, subqueryRoot.get("parent")),
                                    subqueryRoot.get("status").in("STATUS_3","STATUS_4"))
                       );
         return builder.not(builder.exists(subquery));
    }
};