Mysql请求-获取联系人

Question

我有一个联系人表:

from_user_id   to_user_id
300            301
301            298

我正在尝试查找 user_id = 301 的所有唯一联系人。对于该用户，它将是:300 和 298；

我已尝试此请求，但结果错误:

SELECT 
    u.name,
    IF(c.from_user_id = '.(int)$user->id.', c.from_user_id, c.to_user_id) AS uid
FROM 
    `#__contacts`   AS c
LEFT JOIN 
    `#__users`  
AS 
    u   
ON
    uid = u.id

我该怎么做？ 谢谢!

Answer 1

试试这个:

SELECT u.name
FROM `#__contacts` AS c
LEFT JOIN `#__users` AS u ON c.to_user_id = u.id
WHERE '.(int)$user->id.' IN (c.from_user_id, c.to_user_id)
ORDER BY c.created DESC