Geocoder Rails plugin - Near search problem with ActiveRecord

This is dragging at my nerves!

Scenario:

I am using the geocoder plugin: http://github.com/alexreisner/geocoder/

I have two models: Address and Item

the latitude and the longitude are in Address and an Item belongs_to :address

Now, when I try to do a near search:

Item.near(Person.first.address.coordinates, 20)

on an Item it fails with the following SQL:

Unknown column 'latitude' in 'field list':

SELECT *, 3956 * 2 * ASIN(SQRT(POWER(SIN((51.3883 - latitude) * PI() / 180 / 2), 2) + COS(51.3883 * PI()/180) * COS(latitude * PI() / 180) * POWER(SIN((6.65326 - longitude) * PI() / 180 / 2), 2) )) AS distance FROM `items` WHERE ((latitude BETWEEN 51.0984449275362 AND 51.6781550724638 AND longitude BETWEEN 6.188777824785 AND 7.117742175215) AND (`items`.`accepted` IS NULL AND `items`.`taken_by` IS NULL)) ORDER BY distance ASC

Don't look at the weird Math stuff in the query,

the problem lies within the 开发者_高级运维FROM and the WHERE clause because

the latitude and the longitude attributes are part of the address table,

so a simple addition to the Query would solve the problem:

... FROM items, addresses WHERE ...

... null)) AND items.address_id = addresses.id ORDER BY ...

I just want to add a table to the FROM field and a condition :(

I tried using several named_scopes using :include and :joins, but none worked!

Does anybody know a solution to this? How could I insert this into a scoped ActiveRecord object?

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So the Item has address(es) and that's where the longitude and latitude actually exist, right? That's where I think the query is going wrong for you. You could try adding a :joins=>:address ... but I like the following better:

Since all the math occurs in the database, I think you could do:

Address.near(Person.first.address.coordinates, 20)

and then get the items that the addresses belong to, maybe even an :include=>:item or something.