PHP mysqli Prepared Statement with anonymous join - php

Question

I am currently frustrated with preparing one statement - culprit is not preparing it properly, but staying inline with my current function to bin a query with a variable number of parameters. It works in all cases, but this query gives me an unsolveable problem (in one single query) for mysql:
SELECT studios.name,
studios.phone,
locations.zip_code,
locations.location_name,
addresses.street_name,
addresses.stree_nr,
persons.first_name,
persons.last_name,
p.distance_unit
* DEGREES(ACOS(COS(RADIANS(p.latpoint))
* COS(RADIANS(addresses.geo_lat))
* COS(RADIANS(p.longpoint) - RADIANS(addresses.geo_long ))
+ SIN(RADIANS(p.latpoint))
* SIN(RADIANS(addresses.geo_lat)))) AS distance
FROM studios
JOIN ( /* these are the query parameters */
SELECT ? AS latpoint, ? AS longpoint,
? AS radius, 111.045 AS distance_unit
) AS p ON 1=1
CROSS JOIN addresses
ON studios.address = addresses.id
CROSS JOIN locations
ON addresses.location = locations.id
CROSS JOIN persons
ON studios.owner = persons.id
CROSS JOIN studio_types
ON studios.studio_type = studio_types.id
WHERE addresses.geo_lat
BETWEEN p.latpoint - (p.radius / p.distance_unit)
AND p.latpoint + (p.radius / p.distance_unit)
AND addresses.geo_long
BETWEEN p.longpoint - (p.radius / (p.distance_unit * COS(RADIANS(p.latpoint))))
AND p.longpoint + (p.radius / (p.distance_unit * COS(RADIANS(p.latpoint))))
ORDER BY distance
LIMIT 25
The query itself is fully functional - here is a gist of it:
SELECT *
FROM studios
JOIN ( SELECT ? AS latpoint, ? AS longpoint,
? AS radius, 111.045 AS distance_unit
) AS p ON 1=1
now binding it is pretty straight forward:
$query = $this->conn->prepare($query);
if(!$query) throw new Exception($this->conn->error);
$query->bind_params("ddd", $val1, $val2, $val2);
$query->execute();
$query->get_result();
The error that occures by preparing already happens in the first line: Unknown column 'p.latpoint' in 'field list'
Now this is a huge problem. Going around that would probably work with preparing statements with SET #variable = ? - but thats not a preferred situation, as it would break up my current scheme of dispatching my requests.
Is there any oversight or is this simply not possible, due to undefined joins while preparing?
Edit: third method would involve replacing the join and placing values - this would make a very confusuing amount of bind parameters - which would be hard to maintain later.

Answer 1

So, I finally come around for anyone who seeks the same answer like me and I gotta extend where I left with it:
Imagine a class that does all the heavy lifting for you, minimizing issues provides you a simple interface between you and your database. There is a method that takes a statement string, type binding and like this:
protected function __dispatch($query, $types, $arguments) {
error_reporting(0);
$query = $this->conn->prepare($query);
if(!$query) throw new Exception($this->conn->error);
if($types !== "") call_user_func_array(array(&$query, 'bind_param'),
array_merge(array($types), $arguments));
$query->execute();
return $query->get_result();
}
Since placeholders cannot possibly any identifiers (thanks Jon), I can however bind SQL variables just fine. Then I am going to execute something like this:
SELECT *
FROM studios
JOIN ( SELECT #lat AS latpoint, #lon AS longpoint,
#dist AS radius, 111.045 AS distance_unit
) AS p ON 1=1
This gives the possibility to bind variables before - and then use it in the statement, just like this:
public function search_in_range($lat, $long, $distance) {
$this->__dispatch("SET #lat = ?", "d", array(&$lat));
$this->__dispatch("SET #lon = ?", "d", array(&$long));
$this->__dispatch("SET #dist = ?", "d", array(&$distance));
// And finally:
return $this->__dispatch($query, $types, [])->fetch_all();
}
This does the trick to create to have a very simple join with an anonymous set of data and use it in a more complicated statement later on.