php - 将数组与 MySQL 查询结合使用

Question

我正在使用 SELECT 查询来创建值数组。然后我使用另一个选择查询，但我不想排除返回的原始数组值。但我在第二个查询中不断收到错误。我是否正确创建了数组？我的 MySQL 语法正确吗？

我的 PHP:

// Grabs all the users the logged in user is already friends with or following
$already_following_query= "SELECT recipient FROM relations WHERE sender= '".$user_id."'    
AND status= '1' OR status= '2'";
$already_following_result= mysqli_query($connect, $already_following_query)
    or die('Error with already following query');               
$already_following_array= mysqli_fetch_array($already_following_result);

$suggestions_query= "SELECT * FROM users WHERE user_id NOT IN   
'".$already_following_array."' AND user_id != '".$user_id."'";
$suggestions_result= mysqli_query($connect, $suggestions_query)
or die('Error with suggestions query');

Answer 1

NOT IN 子句需要一个数组——您要提供一个字符串。

试试这个:

$array_following_array = implode(", ", $array_following_array);

$suggestions_query = "SELECT * FROM users WHERE user_id NOT IN   ('".$already_following_array."') AND user_id != '".$user_id."'";