Question

我这里有代码加入两个表。但是，我不想从Accounts数据库中获取密码元素。我怎么能这样做？

"SELECT f.*, a.* 
   FROM Following as f 
   JOIN Accounts as a on f.followingUserID = a.id 
  WHERE `followingUserID` = '$acID'

Answer 1

“所有列除外...”没有SQL约定 - 它可以是全部，也可以手动定义列表：

SELECT f.*, 
       a.col1, a.col2,
       a.`col name using spaces not good`
  FROM FOLLOWING as f 
  JOIN ACCOUNTS as a on f.followingUserID = a.id 
 WHERE f.followingUserID = '$acID'

Answer 2

为列命名，而不是全部检索它们。

而不是。*，：

a.ColumnName1，a.ColumnName2等......

Answer 3

如果您不想选择密码元素，则需要更改a.*以单独选择每个列，例如

SELECT f.*, a.account_id, a.name 
FROM following as f 
JOIN accounts as a on f.followingUserId = a.id 
WHERE followingUserID = '$acID'

在JOIN MySQL中选择all on but元素

3 个答案: