如何使用CriteriaQuery转换SQL查询 [英] How to convert SQL Query using CriteriaQuery
问题描述
我想将我的sql查询从SQL转换为CriteriaQuery,我有这个sql查询:
I want to convert my sql query from SQL to CriteriaQuery, I have this sql query:
1)
SELECT * FROM table AS t WHERE id = (SELECT MAX(id) FROM table AS t WHERE t.element_id = 354 AND (name <> 'foo' OR (name = 'bar' AND event = 'foo')));
2)
SELECT tr1.*
FROM table AS tr1
INNER JOIN (SELECT MAX(id) AS id FROM table AS tr WHERE tr.element_id = 354 AND (name <> 'foo' OR (name = 'bar' AND event = 'foo'))) AS tr2
ON tr1.id = tr2.id;
最好的方法是什么?
public Predicate createsubqueryDateGreaterThanTest(CriteriaBuilder cb, Root<? extends Entity> root, Date inputDate){
// create the outer query
CriteriaQuery<Date> cq = cb.createQuery(Date.class);
Root<Table> rootQuery = cq.from(Table.class);
Subquery<Table> sub = cq.subquery(Table.class);
Root<Table> subRoot = sub.from(Table.class);
//sub.select(subRoot);
cq.multiselect(rootQuery);
sub.select(subRoot)
//cq.multiselect(rootQuery.select(cb.max(Table_.elementId)));
//sub.select(cb.greatest(cb.get(Entity_.element).get("id")));
//cq.multiselect(subRoot.select(cb.greatest(Table_.elementId)))
.where(
cb.greaterThanOrEqualTo(subRoot.get(Table_.date), inputDate),
cb.equal(root.get(Entity_.element).get("id"), subRoot.get(Table_.elementId)),
cb.notEqual(subRoot.get(Table_.name), "foo"),
cb.or(
cb.equal(subRoot.get(Table_.name), "bar"),
cb.and(cb.equal(subRoot.get(Table_.event), 'foo'))
)
);
return cb.exists(sub);
}
查询运行,但结果不正确.
The query runs but the result is incorrect.
推荐答案
根据我的记忆,这应该是您的第一个查询的表示形式.
From what I remember this should be the representation of your 1st query.
立即测试
由于数据库没有响应,我现在无法对其进行测试,因此,如果它无法正常工作,我将在稍后编辑答案.
对非常量参数使用ParameterExpression,以确保服务器可以重用查询.否则,它需要分析和重新计划收到的每个新查询.
Use ParameterExpression's for non constant parameters to make sure that the server can reuse the query. Else it need to analyze and replan every new query it receives.
但是在这种情况下,ParamterExpression似乎无法正常工作,可能是一个Hibernate问题(我使用5.4.2.Final进行了测试).
Ps .: 您应该避免使用"sql"关键字作为表标识符,因此不要使用其他名称来命名表"table".
Ps.: You should avoid using 'sql' keywords for table identifiers, so instead of naming your table 'table' use something else.
SELECT * FROM table AS t WHERE id = (SELECT MAX(id) FROM table AS t WHERE t.element_id = 354 AND (name <> 'foo' OR (name = 'bar' AND event = 'foo')));
CriteriaQuery<Table> criteriaQuery = cb.createQuery(Table.class);
Root<Table> root = criteriaQuery.from(Table.class);
Subquery<Integer> sub = criteriaQuery.subquery(Integer.class);
Root<Table> subRoot = sub.from(Table.class);
criteriaQuery.where(
cb.equal(subRoot.get(Table_.element_id), 354),
cb.or(cb.notEqual(subRoot.get(Table_.name), "foo"),
cb.and(cb.equal(subRoot.get(Table_.name), "bar"),
cb.equal(subRoot.get(Table_.event), "foo"))));
sub.select(cb.max(subRoot.get(Table_.id)));
criteriaQuery.where(cb.equal(root.get(Table_.id), sub));
criteriaQuery.select(root);
List<Table> result =
entityManager.createQuery(criteriaQuery)
.getResultList();
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