Doctrine DQL如何编写SELECT EXISTS

Question

这是基于有效的SQL，但我不能让它在DQL中工作

SELECT 
    EXISTS (
        SELECT activity FROM Entity\Activity activity
        WHERE activity MEMBER OF person.activities
        AND activity.name = 'sports'
   ) AS doesSports,
   person.id 
FROM Entity\Person person 

这给出了错误：

[Syntax Error] line 0, col 7: Error: Expected known function, got 'EXISTS'

EXISTS似乎在WHERE之后工作，但在select

中没有

Answer 1

语法不允许所谓的＆＃34;其他表达式＆＃34;在SELECT子句中，只允许使用函数。