我收到关于where子句的错误-不知道如何解决

Question

SELECT 
    Person.id, first_name, last_name
FROM  
    Person 
NATURAL JOIN 
     Writer_Award
WHERE
    (SELECT id FROM Writer_Award 
     WHERE year_of_award - year_born > 50 AND result = 'won'
     GROUP BY Writer_Award.id);

我不断收到错误消息：

WHERE的参数必须为布尔型，而不是字符型

请帮助