php - MySQL 搜索好友查询

Question

我有一个用户表:

user_id | firstname | last name | picUrl ...
    1        bob       smith       null  
    2        bobby     smith       null  
    3        rob       smithies    null  

我还有一张 friend 表:

friend1_id | friend2_id | status | date_established
      1          2        accepted   2018-02-06 10:23:01
      2          1        accepted   2018-02-06 10:23:01

我有一个简单的查询来根据条件($searchString)搜索用户并根据“最佳”匹配对他们进行排序:

$query = "SELECT user_id, firstname, lastname, picUrl, LOWER(CONCAT(firstname, ' ', lastname)) as fullname  
          FROM user
          WHERE LOWER(CONCAT(firstname, ' ', lastname)) LIKE LOWER('%" . $searchString . "%') AND user_id != '{$userId}'
          ORDER BY
             CASE WHEN fullname = LOWER('" . $searchString . "') THEN 0
                  WHEN fullname = LOWER('" . $searchString . "%') THEN 1
                  WHEN fullname = LOWER('%" . $searchString . "%') THEN 2
                  WHEN fullname = LOWER('%" . $searchString . "') THEN 3
                  ELSE 4
                END, fullname DESC
          LIMIT 5";

查询将忽略当前用户:

user_id != '{$userId}'

因为你不能加自己为好友。

如何忽略/不显示已经是 friend 的用户？

示例

我是用户 1。

我搜索“Smith”。

=> 我是用户 1，所以我不是 显示。

=> 用户 2 已经是我的 friend ，所以他们没有显示。

=> 仅显示 Rob Smithies。

Answer 1

再添加一个匹配好友id的条件即可。如下更改您的查询

$query = "SELECT user_id, firstname, lastname, picUrl, LOWER(CONCAT(firstname, ' ', lastname)) as fullname  
          FROM user
          WHERE LOWER(CONCAT(firstname, ' ', lastname)) LIKE LOWER('%" . $searchString . "%') AND (user_id != '{$userId}' AND user_id not in (SELECT friend1_id from friends where friend2_id = '{$userId}') AND user_id not in (SELECT friend2_id from friends where friend1_id = '{$userId}'))
          ORDER BY
             CASE WHEN fullname = LOWER('" . $searchString . "') THEN 0
                  WHEN fullname = LOWER('" . $searchString . "%') THEN 1
                  WHEN fullname = LOWER('%" . $searchString . "%') THEN 2
                  WHEN fullname = LOWER('%" . $searchString . "') THEN 3
                  ELSE 4
                END, fullname DESC
          LIMIT 5";