Doctrine orm 如何为多对多关联编写exists子查询DQL
考虑到下面的实体,有人能帮助我理解如何编写与以下SQL等价的DQL吗?我似乎找不到一个DQL子查询转换为透视表上的select的好例子。谢谢大家!Doctrine orm 如何为多对多关联编写exists子查询DQL,doctrine-orm,doctrine,dql,doctrine-query,Doctrine Orm,Doctrine,Dql,Doctrine Query,考虑到下面的实体,有人能帮助我理解如何编写与以下SQL等价的DQL吗?我似乎找不到一个DQL子查询转换为透视表上的select的好例子。谢谢大家! select * from event a where exists ( select * from event_category b where b.event_id = a.id and b.category_id = 1 ) 实体: /** *
select *
from event a
where exists (
select *
from event_category b
where b.event_id = a.id
and b.category_id = 1
)
实体:
/**
* @Entity
* @Table(name="event")
*/
class Event
{
/**
* @Column(type="integer")
* @Id
*/
protected $id;
/**
* @JoinTable(
* inverseJoinColumns={
* @JoinColumn(name="category_id", referencedColumnName="id")
* },
* joinColumns={
* @JoinColumn(name="event_id", referencedColumnName="id")
* },
* name="event_category"
* )
* @ManyToMany(targetEntity="Category")
*/
protected $categories;
}
/**
* @Entity
* @Table(name="category")
*/
class Category
{
/**
* @Column(type="integer")
* @Id
*/
protected $id;
}
请看一看
你的例子可以写成:
SELECT event FROM Event event
WHERE EXISTS (
SELECT cat FROM Category cat
WHERE IDENTITY(cat.event) = event.id
AND cat.id = 1
)
现在我可能错了,但我认为这里不需要子查询
如果需要具有给定类别的事件:
SELECT event FROM Event event JOIN event.category WHERE category.id = 1