致命错误：在非对象上调用成员函数bind_param（）

I try some codes to build a RESTful API Web Service using PHP and slim framework. (I'm using Advanced Rest Client for testing this code)

This is my codes.

private function isUserExists($email) { $stmt = $this->conn->prepare("SELECT id from users WHERE email = ?"); $stmt->bind_param("s", $email); $stmt->execute(); $stmt->store_result(); $num_rows = $stmt->num_rows; $stmt->close(); return $num_rows > 0; }

and then I got this error.

Fatal Error : Call to a member function bind_param() on a non-object on Line 113

Line 113 is : $stmt->bind_param("s", $email);

I've been looking for a solution of this problem since 2 weeks ago.

Thanks before guys :))

The problem lies in $this->conn->prepare, which does not return an object, as you would expect.

For mysqli, prepare() returns FALSE on error. You can check the error message using $this->conn->error.

This code should print your error in case of failure:

private function isUserExists($email) {
    $stmt = $this->conn->prepare("SELECT id from users WHERE email = ?");
    if ($stmt === FALSE){
        die($this->conn->error);
    } else  {
        $stmt->bind_param("s", $email);
        $stmt->execute();
        $stmt->store_result();
        $num_rows = $stmt->num_rows;
        $stmt->close();
        return $num_rows > 0;
    }
}