表结构发下

先测试下下面这个写法是否报错

select c.*
      ,case when exists(select 1
                          from project_activity_entry a
                         where activity_id=c.id 
                           and a.deleted=0 
                           and a.user_id=1
                           and a.id is not null
                       ) 
              then 1 else 0
        end as flag
  from project_activity c
 where c.deleted=0 
   and c.id=1805791272344064002;

两张表的创建语句发下看看