Question

我正在设计一个堆栈交换软件，并且我有这个查询来检索那些我的客户拥有帐户的帐户名

SELECT TOP (200) account.account_no, account_type.account_type_id, account_type.account_name, customer.first_name
FROM account 
     INNER JOIN customer ON account.customer_id = customer.customer_id 
     INNER JOIN account_type ON account.account_type = account_type.account_type_id
WHERE (account.customer_id = 2)

现在我要选择那些我的客户没有帐户的帐户

Answer 1

您可以将RIGHT JOIN与WHERE account.customer_id is null一起使用

SELECT TOP(200) account.account_no,
       account_type.account_type_id,
       account_type.account_name,
       customer.first_name
  FROM account
 RIGHT JOIN customer
    ON account.customer_id = customer.customer_id  
 INNER JOIN account_type
    ON account.account_type = account_type.account_type_id
 WHERE account.customer_id is null

Answer 2

此查询：

select t.account_type_id from account a 
inner join account_type t ON a.account_type = t.account_type_id
where a.customer_id = 2

包含要排除的所有account_type_id。
因此，将它与NOT IN子句一起使用：

select account_type_id, account_name 
from account_type
where account_type_id not in (
  select t.account_type_id from account a 
  inner join account_type t ON a.account_type = t.account_type_id
  where a.customer_id = 2
)

Answer 3

我会使用NOT EXISTS：

SELECT act.*
FROM account_type act
WHERE NOT EXISTS (SELECT 1
                  FROM account a
                  WHERE a.account_type = act.account_type AND
                        a.customer_id = 2
                 );

请注意，customer表不是必需的。

如何在SQL Server中反转语句

3 个答案: