预准备语句中的mysqli_num_rows返回0

Question

我有一个看起来像这样的函数，其目的是通过电子邮件检查数据库中是否已存在用户：

function b_check_if_email_exists(mysqli $db_object, $email)
{
    $statement = $db_object->prepare("SELECT * FROM users WHERE email = ?");
    $statement->bind_param("s", $email);
    $statement->execute();
    return ($statement->num_rows > 0);
}

但是，由于false始终为0，函数始终返回$statement->num_rows。在MySQL Workbench中输入查询SELECT * FROM users WHERE email = "email@user.com"可以完美地运行。任何帮助将不胜感激。

Answer 1

尝试：

function b_check_if_email_exists(mysqli $db_object, $email)
{
    $statement = $db_object->prepare("SELECT * FROM users WHERE email = ?");
    $statement->bind_param("s", $email);
    $statement->execute();
    $statement->store_result();
    return ($statement->num_rows > 0);
}