laravel - 从 Laravel 的一行中选择单列？

Question

如何从 Laravel 4 的单行中获取单列？

这是我正在尝试的:

return DB::selectOne("
    SELECT EXISTS(
        SELECT *
        FROM permissions p
            JOIN role_permissions rp ON rp.permission_id=p.id
            JOIN user_roles ur ON ur.role_id=rp.role_id
        WHERE ur.user_id=? AND p.code=?
    )
    ",[Auth::user()->id,$perm_code]);

selectOne虽然返回这个丑陋的对象:

object(stdClass)#297 (1) {
  ["EXISTS(
                SELECT *
                FROM permissions p
                    JOIN role_permissions rp ON rp.permission_id=p.id
                    JOIN user_roles ur ON ur.role_id=rp.role_id
                WHERE ur.user_id=? AND p.code=?
      "]=>
  string(1) "0"
}

有什么更好的吗？

使用 PDO 也很丑陋:

$stmt = DB::getPdo()->prepare("
    SELECT EXISTS(
        SELECT *
        FROM permissions p
            JOIN role_permissions rp ON rp.permission_id=p.id
            JOIN user_roles ur ON ur.role_id=rp.role_id
        WHERE ur.user_id=? AND p.code=?
    )
    ");
$stmt->execute([Auth::user()->id,$perm_code]);
return (bool)$stmt->fetchColumn();

Answer 1

用这个:

DB::table('users')->pluck('columname');

从内联文档:

/**
 * Pluck a single column's value from the first result of a query.
 *
 * @param  string  $column
 * @return mixed
 */