Question

I have a model with some relationship that is best described if I write my own SQL. To simplify, I write something like this (in, say MyModel.rb):

has_many :platform_spots, :finder_sql => "SELECT * FROM platform_spots WHERE id=#{id}"

in the model description.

If I now run rails console, and try to pull

MyModel.find(:first)

I get

NameError: undefined local variable or method `id' for #<Class:0x000001039e4b80>

I figure its because I need to use single quotes, so I change it to

has_many :platform_spots, :finder_sql => 'SELECT * FROM platform_spots WHERE id=#{id}'

Now, in the console

ecs = MyModel.find(:first)
ecs.platform_spots

I get the errors

  PlatformSpot Load (0.2ms)  SELECT * FROM platform_spots WHERE id=#{id}
Mysql::Error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1: SELECT * FROM platform_spots WHERE id=#{id}
ActiveRecord::StatementInvalid: Mysql::Error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1: SELECT * FROM platform_spots WHERE id=#{id}

Answer 1

Try rewriting it like this:

has_many :platform_spots, :class_name => "PlatformSpot",
            :finder_sql => proc {"select * from platform_spots where id = #{id}"}