sql - 不是时 Oracle 缺少括号

Question

SELECT company_name
FROM empl_company s
WHERE NOT EXISTS 
(
    (SELECT city
     FROM empl_company
     WHERE company_name = 'Small Bank Corporation'
     )
     EXCEPT
    (SELECT city
     FROM empl_company k
     WHERE k.company_name = s.company_name
     ) 
);

我变成了一个错误 ORA-00907：缺少右括号，谁能告诉我有什么问题？

Answer 1

运算符在 Oracle中EXCEPT调用；MINUS

select company_name
from empl_company s
where not exists (
  select city
  from empl_company
  where company_name = 'Small Bank Corporation'
  MINUS
  select city
  from empl_company k
  where k.company_name = s.company_name
);

Answer 2

从不存在的emp1_company s中选择company_name（从emp1_company中选择城市，其中company_name ='Small Bank Corporation'和城市（从empl_company k中选择城市k.company_name = s.company_name））；