Incrementing Integer Without Parsing Array - php

Question

I have a php form that submits to MySQL, and a 2nd php form that uses the value stored via the first.
The highest value in the database for booth_member is currently 3. In the example below, = $booth_member should be equal to 4, but instead always returns 2.
$membersql = $mysqli->query("SELECT booth_member FROM users WHERE booth_number = '{$user['booth_number']}' ORDER BY booth_member DESC LIMIT 1");
$booth_member = $membersql + 1;
echo $booth_member;
If I try and echo $membersql, it simply returns 'array.'

Answer 1

mysqli::query returns a ressource object, that's why it's not working. Some code to fix it:
$membersql = $mysqli->query("SELECT booth_member FROM users WHERE booth_number = '{$user['booth_number']}' ORDER BY booth_member DESC LIMIT 1");
if($membersql->num_rows < 1)
{ /* error handling goes here */ }
else
{
$res_array = $membersql->fetch_assoc(); // save result as array
$booth_member = $res_array["booth_member"] + 1;
echo $booth_member;
}
Be sure to escape $user['booth_number'] before to prevent sql injection.
For more info, check the mysqli::query documentation :)

Answer 2

You require a bunch of try/catch code around this for a production system, but to test:
$result = $mysqli->query("SELECT booth_member FROM users WHERE booth_number = '{$user['booth_number']}' ORDER BY booth_member DESC LIMIT 1");
$booth_member = $result->fetch_object('booth_member');
++$booth_member;
echo $booth_member;

Answer 3

That's because it's an array. I believe you are trying to do:
$booth_member = $membersql['booth_member'] + 1;