问题描述
我有两个实体,一个是Client
,另一个是Transactions
,它们分别链接到@OnetoMany
。
我想使用Querydsl创建一个查询,该查询将根据客户的交易次数过滤客户。基本上我想要这个SQL查询
SELECT * FROM client WHERE id IN (SELECT client_id
FROM (SELECT client_id,count(client_id) as 'count' from transaction group by client_id) as t
where t.count >= 10)
在Querydsl中完成。问题是我想返回一个BooleanExpression
,以便可以进一步聚合查询,即AND
或OR
与其他查询合并。
Querydsl实体分别为QClient
和QTransaction
。
这是我当前的代码,
QClient client = QClient.client1;
QTransaction transaction = QTransaction.transaction;
var count = Expressions.numberPath(Long.class,"count");
var subquery = JPAExpressions.select(transaction.client.id,transaction.client.id.count().as(count))
.from(transaction).groupBy(transaction.client.id).where(count.gt(depositCount)).select(transaction.client.id);
return client.id.in(subquery);
此格式不起作用。
解决方法
如何?
请注意,这与我在https://github.com/gtiwari333/spring-boot-web-application-seed
的测试项目有关。但是您可以轻松地将它们应用于表。
public void doQuery() {
QArticle qArticle = QArticle.article;
QUser user = QUser.user;
var subquery1 = JPAExpressions
.select(qArticle.createdByUser.id)
.from(qArticle)
.groupBy(qArticle.createdByUser.id)
.having(qArticle.id.count().gt(5));
BooleanExpression exp = user.id.in(subquery1);
BooleanExpression exp2 = qArticle.title.length().lt(15);
List<Article> ar = from(qArticle)
.join(user).on(qArticle.createdByUser.id.eq(user.id))
.select(qArticle)
.where(exp.and(exp2))
.fetch();
System.out.println(ar);
}
此外,您的查询也可以简化。
SELECT * FROM client WHERE id IN
( SELECT client_id FROM
(SELECT client_id,count(client_id) as 'count' from ransaction group by client_id)
as t where t.count >= 10)
收件人:
SELECT * FROM client
WHERE id IN ( SELECT client_id
FROM
TRANSACTION
GROUP BY
client_id
HAVING
count(client_id)> 10)