php - MySQL 查询中的逗号

Question

$sql_query_posts = "SELECT * FROM `posts`";

$sql_form_permission = mysql_query("SELECT * FROM `integrations` WHERE `rank_id`='$user_level' AND `mode`='form_per'");
    if ( mysql_num_rows($sql_form_permissions) > 0 ) {

现在我正在努力的部分:

   $sql_query_posts .= " IN (";
    while ( $row_form_permissions = mysql_fetch_assoc($sql_form_permissions) ) { 
    $sql_query_posts .= $row_form_permissions['form_id'] . ",";
    }
    $sql_query_posts .= ")";
    }

我希望输出是这样的:

SELECT * FROM `posts` IN (4, 3, 2)

但是上面的代码给出了这样的输出:

SELECT * FROM `posts` IN (4, 3, 2,)

所以我必须去掉最后的逗号。我怎样才能确保脚本禁用最后一行的逗号。

Answer 1

我会为此使用 implode:

$post_ids = array();
while ( $row_form_permissions = mysql_fetch_assoc($sql_form_permissions) ) { 
    $post_ids[] = $row_form_permissions['form_id'];
}

$sql_query_posts .= " IN (" . implode(",", $post_ids) . ")";