Cake php 2: Sort on 2nd-level Association - sorting

Question

I wrote a post last year about this. The first part, how to sort on a 1st-level Association, was answered (thanks again!) but the second part of the question, about how to sort on a 2nd-level Association, was never answered. It wasn't a big issue, and we ran out of time so I never actually implemented it. But now we're updating the web, and the client wants this functionality, namely, with the following Models:
Company belongsTo City
City belongsTo Country, hasMany Companies
Country hasMany Cities
In the Companies page I want to sort on City.Country.name. Even putting recursive=2, it doesn't work. Cake ignores my 'order' condition; in the generated SQL there simply is no 'order by' at all.
It works fine if I sort on sort on City.name, however.
Is there any way to do this? I've been scouring the docs and Stackoverflow. I've looked at virtual fields, custom queries.
One way that seemed to look promising was to use Model->query() in the CompaniesController:
$companies = $this->Company->query("SELECT * FROM companies com left join cities c on c.id = com.city_id left join countries c2 on c2.id = c.country_id order by c2.name");
But, is this the best/only way to go? And do I not have to now worry about overriding pagination? I don't mind that but I would still like to use "normal" built-in pagination elsewhere for Companies. Will that be possible?
Also, in the examples in the docs, it says to do something like Model->query('SELECT * FROM pictures AS Picture LIMIT 2') so the resulting Array will use the model name as the array key. But how can I do this with my complex query? Where would the "AS" go?
I was rather hoping I'd be able to avoid having to do it like this though. Is there a simpler way to do it?
EDIT
Hi, thanks for your help. By "pagination technique" you mean Cake's built-in pagination? Yes, that's what I want. My default paging conditions in the controller are:
$this->paginate = array('conditions' => 'order' => array('Company.name' => 'ASC');
And it sorts on company name. The SQL is
SELECT Company.id, etc. FROM companies AS Company LEFT JOIN cities AS City ON Company.city_id = City.id order by Company.name
And when I create paging links in the View like this
$paginator->sort('City.name')
it adds these parameters to the url
.../companies/sort:City.name/direction:desc
it sorts on City name. The SQL is
SELECT Company.id, etc. FROM companies AS Company LEFT JOIN cities AS City ON Company.city_id = City.id order by City.name
But when I try this:
$paginator->sort('City.Country.name');
it adds these parameters to the url
.../companies/sort:City.Country.name/direction:asc
and the generated SQL is
SELECT Company.id, etc. FROM companies LEFT JOIN cities AS City ON (Company.city_id = City.id)
It completely ignores the 'sort' condition, and there is no 'order by' at all. I'm not sure why. Maybe Cake just can't do this? I have 'recursive' set to 2.
The other option is Model->query, which I tried and got working, but I'd rather not use because I would have to override paginate and paginateCount methods, which isn't that hard, but the problem is that on the same page, and on other pages, I am already using 'normal' Cake paging for Companies. So if I override paginate and paginateCount, won't I have to change all of those pages to use the new, over-ridden paging? I'd like to avoid that, because it seems like overkill, and is working fine everywhere else, except for this one case.
Any assistance much appreciated.
Bob

Answer 1

Well, in the end I managed it, after perusing the docs and many examples online, like this:
First, in the Model, declare and implement custom findMethods.
class Company extends AppModel {
public $findMethods = array('companiesOrderByCountry' => true);
protected function _findCompaniesOrderByCountry($state, $query, $results = array()) {
if ($state === 'before') {
$query['joins'] = array(
array(
'table' => 'cities',
'alias' => 'City',
'type' => 'LEFT',
'conditions' => 'City.id = Company.city_id'
),
array(
'table' => 'countries',
'alias' => 'Country',
'type' => 'LEFT',
'conditions' => 'Country.id = City.country_id'
)
);
$query['order'] = array('Country.name' => 'asc');
return $query;
}
return $results;
}
Then in the Controller, conditionally call it, based on named params in request
if (!empty($this->request->params['named']['sort']) && $this->request->params['named']['sort'] == 'Country.name') {
// here we need to sort on Country.name. Call custom findMethod in Model
$this->paginate = array('companiesOrderByCountry','limit' => 10);
$companies = $this->paginate();
$this->set(compact('companies'));
} else {
// do a normal search
$this->paginate = array('limit' => 10,'conditions' => array('order' => array('Company.nombre' => 'ASC' ));
$companies = $this->paginate('Company');
$this->set('companies', $companies);
}
Lastly, create a link, passing the named parameter, in the .ctp
<?php $paginator = $this->Paginator; ?>
<?php echo $paginator->sort('Country.name', __('Country')); ?>
There's probably a more elegant way to do this, but I was sick of dealing with it. The generated sql is just what I need and now I can sort on Country, which is a 2nd-level (Company->City->Country) association.
Hope this helps someone someday!
Bob

Answer 2

If you want to try using the query method, then I would not use the asterisks (*). Instead explicitly list the fields you want.
Your query should look something like this: {My personal best practice, use COALESCE on fields that may be NULL - especially when using a LEFT JOIN}
SELECT companies.name AS CompanyName,
COALESCE(cities.name, 'Unknown') AS CityName,
COALESCE(countries.name, 'Unknown') AS CountryName
FROM companies
LEFT JOIN cities
ON companies.city_id = cities.id
LEFT JOIN countries
ON cities.country_id = countries.id
ORDER BY CountryName, CityName
Use AS to separate the field from its alias. It also separates a table from its alias ( e.g., the examples you listed.) AS is optional, but I feel it adds to readability.
--
(If you want to try the pagination technique, please show the MySQL SELECT statement that is failing when RECURSIVE = 2, along with what the controller's code looks like - specifically the 'order'=> array)