用于嵌入式 @ElementCollection 的具有嵌套查询的条件生成器 IN 子句

Question

我有 User 和 Address 实体（实际上是其他实体，只是为了简化）。

@Entity
public class User {
    @Id
    @GeneratedValue
    protected long id;
    ...

    @ElementCollection
    @CollectionTable(name = "address",
        joinColumns = {@JoinColumn(name = "user_id")})
    @Column(name = "street")
    private List<Address> addresses;

    ...
}

@Embeddable
public class Address {
    private String street;
    ...
}

如何对Address 进行嵌套查询并在IN 子句中使用它？我期望的结果查询`select * from user u where u.id in (select user_id from address where street like '%Green%');

Root<User> root = ...; // Root query already exists

CriteriaQuery<Address> cq = builder.createQuery(Address.class);
Root<Address> addressRoot = cq.from(Address.class);

cq.select(addressRoot.get("user_id"))
    .where(
        builder.like(
            addressRoot.get("street"),
            "%Green%"
        )
    );

Predicate .... = criteriaQuery.where(root.get("id").in(cq))

我尝试过类似的方法，但它不起作用 - Address 它不是实体，我无法用它创建 CriteriaQuery。 重要提示：我不能使用root.join("addresses").get("street").like(...) 有几个原因

Answer 1

您需要使用存在子查询，如下所示：

Root<User> root = ...; // Root query already exists

CriteriaQuery<Address> cq = builder.createQuery(Address.class);
Subquery<Integer> subquery = cq.subquery(Integer.class);
Root<User> correlatedRoot = subquery.correlate(root);
Join<User, Address> addressRoot = correlatedRoot.join("addresses");

cq.select(addressRoot.get("user_id"));
subquery.where(
        builder.like(
            addressRoot.get("street"),
            "%Green%"
        )
    );

Predicate .... = criteriaQuery.where(builder.exists(subquery));